Allah [may He be Glorified] said: "Show forgiveness, enjoin what is good, and turn away from the foolish." (7:199)
This verse deals with good behaviour with people. It explains that, when dealing with people, the following should be considered:
1. Showing forgiveness: to accept from people whatever they are able to perform of actions and behaviour. No soul shall be burdened with anything beyond its capacity. One should thank every person in return for his good words or deeds, or even what is less than that. He is also ordered to overlook their shortcomings and not to reveal their defects. He is also directed not to be arrogant towards others due to their young age, insanity or poverty, but he should treat all of them well in a manner that pleases them and conforms with the circumstances.
2. Enjoining Ma'ruf: the word Ma'ruf stands for every good act and saying and perfect manner observed when dealing with people, whether relatives or otherwise. Thus, it is expected from a Muslim in all his dealings with people to be beneficial in different ways: to teach them of his knowledge, urge them to do good in terms of maintaining good relation with kinsfolk or reconciliation between disputants, offer useful advice, propose prudent opinion, help others to indulge in righteous acts and piety, warn people against doing bad deeds, and guide them to achieve interests that pertain to either the religion or to their mundane affairs.
3. Turning away from the foolish and not reciprocating their conduct. This includes not to harm he who harmed you by his speech or acts, rather it is better to adopt a tolerant attitude; by forgiving those who injured you, by giving those who deprived you, by maintaining the ties of kinship with those who severed such relations with you, and by being just with those who treated you unjustly.
See Tafsir Ibn Sa'di, p.276 (Al-Luwaihiq Edition).