Prohibition of Reviling a Muslim without any cause

When he left, someone said to him: "May Allah disgrace you!'' The Prophet (sallallaahu alayhi wa sallam) said, "Do not help Satan overcome him by uttering such words.'' [Al-Bukhari].
http://www.gowister.com/books/riyad-us-saliheen-266.html

Prohibition of Despising Muslims

"Once someone said: `By Allah! Allah will not forgive such and such (a person).
http://www.gowister.com/books/riyad-us-saliheen-273.html

Prohibition of Deriding one's Lineage

To defame someone's lineage means to disgrace or humiliate somebody by saying to him or to her: "Your father belongs to such and such profession'' or "Your mother is such and such / so-and-so'' or
http://www.gowister.com/books/riyad-us-saliheen-275.html

Prohibition of Deceiving others

Commentary: To incite or provoke someone's wife or slave against her husband or his master or to create hatred between the two is a great crime,
http://www.gowister.com/books/riyad-us-saliheen-276.html

Prohibition of Cruelty

To make someone stand in a sizzling hot day and pour oil over his head is one type of tormenting people.
http://www.gowister.com/books/riyad-us-saliheen-282.html

Undesirability of giving a Gift and then ask back for it

"He who gives something (to someone) as a gift and then gets it back (from him or her) is like a dog which eats its own vomit.
http://www.gowister.com/books/riyad-us-saliheen-285.html

Prohibition of taking Ar-Riba (The Usury)

If someone is in need of money, the rich should fulfill his needs for the sake of Allah's Pleasure or give him a loan without interest.
http://www.gowister.com/books/riyad-us-saliheen-287.html

Prohibition of Show-off

He who does a thing for the sake of someone else beside Me, I discard him and his polytheism..'' [Muslim].
http://www.gowister.com/books/riyad-us-saliheen-288.html

Things not to be Considered as Showing off

Expression of such good opinion about him by the public is akin to a declaration that Allah is pleased with him. Sincere admiration and praise of someone by the public is not a disqualification.
http://www.gowister.com/books/riyad-us-saliheen-289.html

Prohibition of Meeting a non-Mahram Woman in Seclusion

If the husband begins to suspect that his wife has illicit relations with someone else, he might kill her or divorce her out of his sense of honour.
http://www.gowister.com/books/riyad-us-saliheen-291.html