1. Trust Allah

Trusting in Allah is the expense for achieving whatever worthwhile and the ladder toward whatever elevating.

al-'Allama al-Majlisi, Bihar al-anwar, vol.78, p.364.

2. The All-Present 

Feeling Allah in every breath is more advantageous than exhausting your body in worshipping Him.

al-'Allama al-Majlisi, Bihar al-anwar, vol.78, p.364.

3. Four Things a Believer Needs 

The believer is in need of Allah's favor, his/her inner guide, and being open to the goodwill of the well-wishers.

 Ibn Shu'ba al-Harrani, Tuhaf al-'uqul, p. 457.

4. Visiting Friends 

Visiting your friends, even for a short time, improves your health and elevates your mind.

al-Shaykh al-Mufid, Al-Amali, p.329.

5. Do not Trust Unheedfully 

Trusting someone before making sure [of his/her personality] ends up in pain and catastrophe.

al-'Allama al-Majlisi, Bihar al-Anwar, vol.78, p.364.

6. Prosperity 

The believer prospers in not depending on others.

 al-Shaykh al-Mufid, Al-Amali, p.109.

7. The Hidden Secret

Life reveals the hidden secrets to you, [as it goes by]. 

 al-Shaykh al-Mufid, Al-Amali, p.365.

8. Allah's Supervision

Know that you are constantly under Allah's supervision, so beware of yourself.

Ibn Shu'ba al-Harrani, Tuhaf al-'uqul, p. 455.

9. Wrong Deeds

If you approve of a wrong deed, you will be considered to have a share in committing it.

 al-'Allama al-Majlisi, Bihar al-Anwar, vol.75, p.82.

10. Ask Your Needs from Allah

Whoever turns to anyone other than Allah, Allah will leave his/her matters to that other person. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.68, p.155.

11. Don't Be Pretentious 

Don't pretend to be Allah's friend while being His enemy in secret. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p.365.

12. Going through a Deed

If you are confused about entering a deed, you'll be desperate in coming out of it.

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p.364.

13. Receiving Affection

You receive affection through gaining three characteristics; being fair in your relations, sympathizing [with others] in their hardship and happiness, and keeping your heart unstained [from sins]. 

Baha' al-Din 'Ali b. 'Isa al-Irbili, Kashf al-ghumma fi ma'rifat al-a'imma, vol.3, p.139.

14. A Mischievous Person

Avoid befriending a mischievous person, since he/she is like a bare blade whose look is alluring, while its impact [wound] is hideous. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.74, p.198.

15. Generosity 

The good that generous people do for others benefits them more than the ones in need of help since its reward, honor, and reputation belong to them. Therefore, any favor that one does first benefits him/herself. So he/she shouldn't expect to be gratified for what he/she has done. 

Baha' al-Din 'Ali b. 'Isa al-Irbili, Kashf al-ghumma fi ma'rifat al-a'imma, vol.3, p.137.

16. Sincerity 

The best worship is sincerity in [intention]. 

Warram b. Abi Firas al-Hilli, Tanbih al-khawatir wa nuzhat al-nawazir , vol.2, p.109.

17. Listening to Someone

When you listen to a speaker, you have turned into his/her slave (follower); if the speaker's words are directed toward Allah Almighty, the listener has glorified Allah, and if his/her words are directed toward Satan, the listener has worshipped Satan.

 Muhammad ibn Ya'qub al-Kulayni, al-Kafi, vol.6, p.434.

18. Being Thankful 

The blessing, which is not gratified, is like a sin, which has not forgiven. 

Hasan ibn Muhammad Deilami, Aalam al-din fi Sifat al-Moumenin, p.309.

19. Relying on a Mischievous Person

The least punishment of the one who relies on a mischievous person is being deprived of his/her aspiration.

Aziz Allah, Atarodi, Mosnad Imam al-Jawad (AS), p.248.

20. Unwise Words

Unwise words cause many disputes.

 Sabbagh al-Maliki, Al-Fusul al-muhimma fi ma'rifat al-a'imma, p.274.

21. Piety

If you stay pious despite being in a chaotic situation, Allah will bestow His mercy upon you and show you a way out.

Sabbagh al-Maliki, Al-Fusul al-muhimma fi ma'rifat al-a'imma, p.274.

22. Death

Death is like your sleep at night, except that the fatal sleep is longer, and you won't wake up from it until the Day of Judgement.

al-'Allama al-Majlisi, Bihar al-anwar, vol.3, p.134. 

23. Hope

The needs are requested by hope and answered by divine will. Undoubtedly, the best blessing is well-being.  

Hasan ibn Muhammad Deilami, Aalam al-din fi Sifat al-Moumenin, p.309.

24. Your Trustee and Guardian

The one whom Allah is his/her trustee and guardian will never go astray or get disappointed. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.68, p.155.

25. Salvation

Whoever desires Allah will surely be saved. 

 al-'Allama al-Majlisi, Bihar al-anwar, vol.68, p.155.

26. Foresight

Unexpected incidents and calamities will devour the one who lacks foresight.

al-'Allama al-Majlisi, Bihar al-anwar, vol.68, p.340.

27. Blaming People

Blaming people without any evidence or reason causes anger and distress, and they will never forgive you for this.

al-'Allama al-Majlisi, Bihar al-anwar, vol.71, p.181.

28. Your Daughter's Suitor

If you are sure about the piety, faith, and trustworthiness of your daughter's suitor, agree to his request; otherwise, it will lead to great misfortune and ruin. 
Muhammad ibn Ya'qub al-Kulayni, al-Kafi, vol.5, p.347.

29. The Ignorant

There will be no dispute among people if the ignorant remain silent.

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 81.

30. Consider Different Aspects of a Task

Whoever accepts and submits [to a task, command, etc.] without considering its different aspects, has exposed him/herself to destruction and distress. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 364.

31.  Dependence and Independence 

People will be dependent on the one who, by relying on Allah, considers himself independent. And the pious will naturally be favored by people even if they aren't pious themselves. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 79.

32. Learning

Strive in gaining knowledge and wisdom, and know that learning is obligatory (Wajib) and discussing [what has been learned] is recommended (Mustahab).

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 80.

33. Imam Jawad (AS) Knowledge 

Knowledge is the means of helping friends and relatives, the reason for and sign of fairness, a gift and means of entertainment in gatherings, the human's companion in travel, and one's mate in lonely times. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 80.

34. Modesty and Humility 

Modesty and humility are the adornments of knowledge and wisdom.

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 91.

35. Politeness 

Politeness and being good-natured are signs of reason and forbearance.

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 91.

36. Patience, Poverty, Impulses

Rely on patience in all your life, see poverty as your companion, and stand against your whims and impulses. 

 al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 358.  

37. Prayer (Salat)

One should perform prayer (Salat) in a modest manner. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.74, p. 131.

38. Repentance

The conditions for your repentance to be accepted by Allah are feeling regret at heart, asking for forgiveness by the tongue, compensating for your mistakes, and being determined not to commit those sins again. 

Baha' al-Din 'Ali b. 'Isa al-Irbili, Kashf al-ghumma fi ma'rifat al-a'imma, vol.2, p.349.  

39. Two Kinds of Knowledge 

There are two kinds of knowledge; one is heard, and the other is practiced [besides being heard]. There is no use in the knowledge that is heard but not practiced. 

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 80.

 40. Injustice

The one who does an injustice, the one who participates in it, and the one who is content with it all have a share in it.  

al-'Allama al-Majlisi, Bihar al-anwar, vol.75, p. 81.

The responsibilities of a Muslim towards family, relatives and other Muslims in general, were already reviewed in an article. Here one's responsibility in Islam towards neighbors, friends, and enemies are discussed.

The Responsibility in Islam Towards Neighbors 

Doing good to neighbors is highly emphasized in Islamic teachings: “Worship Allah and … be good to … the near neighbor and the distant neighbor” (4:36). Prophet Muhammad (PBUH&HP) advised Imam Ali (AS) to honor the neighbors, even if they are disbelievers (Kafir) [1]. Imam Ali (AS) said that Prophet Muhammad (PBUH) used to invite repeatedly to doing good to neighbors such that we thought he (PBUH) was going to consider an inheritance for them [2].

The rights of neighbors on one another as an important responsibility in Islam, are:

To honor them in their presence, and to help and care about them when they are absent [3]. It includes visiting neighbors when they are sick, to assist their funeral, and to offer them your tasty meals that smell good [4];
To keep their secrets. It means that not to look for their faults and errors. And, if ever you become aware of some of their faults, do not reveal them but try to conceal their deficiencies [3];
Do not leave neighbors alone in difficulties [3]; e.g., help them in case of financial needs [4];
Do not be jealous of them if God grants them some blessings [3];
Ignore their errors to yourself and forget about them. If ever they do wrong to you unintentionally, be patient and in peace with them [3];
Do not let others talk behind their back and reveal the deficiencies of your neighbors here and there [3].
Giving priority to the neighbors. It is narrated from Imam Hassan (AS) that Lady Fatima al-Zahra (AS) used to pray firstly for the neighbors and then for members of the family [5]. 

According to Imam Sadiq (AS), having good behavior and interaction with neighbors increases the provision (Rizq) [6]. Prophet Muhammad (PBUH) advised to respect neighbors as much as one should respect his\her mother [6] and he (PBUH) said: “God bless whoever does good to his\her neighbors” [7]. On the contrary, whoever sleeps peacefully at night while one of the his\her neighbors is hungry, God will deprive him of his blessings on the judgment day [8]. The same will happen to whoever annoys his\her neighbors [1]. 

Take your time and think about these attitudes towards the neighbors. Life will be surely much agreeable and peaceful if we improve our social interactions with our neighbors within the Islamic framework.

The Rights of Friends and Companions

Having a good companion is known as a blessing; on the contrary, a bad one is like a disaster [9]. Friends and companions have certain rights one over the other including:

To interact with them with generosity as much as you can, otherwise, be fair to them [3];
To be smiling when you meet them and to receive them modestly [3];
To respect them as they respect you [3];
To be the first one who does good to the other one, otherwise, try to compensate properly [3];
To help them in difficulties and whenever they are in need, as Imam Ali (AS) advised to [10];
To hold them in great affection according to Imam Ali (AS) [11];
Not to reveal their deficiencies and mistakes;
To encourage them in obedience to God and to prevent them from committing sins [3];
To be honest with them and not to cheat [3]; e.g., nor to talk behind their back neither to reveal their deficiencies and to guard their secrets;
To be trustworthy whenever they rely on you [3].

The Responsibility in Islam Towards the Enemies

The enemy here means a person whom one is in conflict with. There are some recommendations in Islamic resources on how to treat enemies and what is one's responsibility in Islam towards them:

To be fair with them [12]. According to Imam Sadiq (AS), a real believer (Mu'min) does not oppress his\her enemies [13];
To testify in favor of the enemies if they are right [14] even if your testimony is against yourself [3];
To keep the promises you made to your enemies [15];
To forgive and tolerate them, if possible [3]. According to Imam Ali (AS), there is a virtue in forgiving enemies [16];
To talk nicely and shortly with whoever you have complained of [3], to argue with them in a way that is best (16:125), and not to ignore their rights if ever you are wrong [3].

References:

1. M. Shoueiri “Jami’ al-Akhbar”, p. 84.
2. Shaykh al-Kulayni, “Al-Kafi”, vol. 7, p. 51.
3. Imam Zayn al-'Abidin (AS), “Treatise On Rights (Risalat al-Huquq)”.
4. responsibility towards others
5. Shaykh al-Saduq, "Ilal Al-Shara'i", p. 181
6. Shaykh al-Kulayni, “Al-Kafi”, vol. 2, p. 666.
7. Shaykh al-Saduq, “Al-Amali”, p. 288.
8. Shaykh al-Kulayni, “Al-Kafi”, vol. 2, p. 668.
9. “Ghurar al-Hikam wa Durar al-Kalim”, T. 4719-4720.
10. “Nahj al Balaqa”, p. 494.
11. “Ghurar al-Hikam wa Durar al-Kalim”, T. 9665.
12. Ibn Shu’bah, “Tuhaf al-Uqul”, p. 88.
13. Shaykh al-Kulayni, “Al-Kafi”, vol. 1, p. 47.
14. Shaykh al-Saduq, “Sifat al-Shia”, p. 24.
15. “Nahj al Balaqa”, p. 53.
16. “Ghurar al-Hikam wa Durar al-Kalim”, p. 435.