Riyad as-Salihin (The Meadows of the Righteous)
by Imam Nawawi
271. Chapter: On the prohibition against spying
Allah Almighty says, "And do not spy on one another," (49:12)
and the Almighty says, "And those who abuse believing men and woman, when they have not merited it, bear the weight of slander and clear wrongdoing." (33:58)
1570. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Beware of suspicion. Suspicion is the falsest kind of speech. Do not spy or pry. Do not be rivals nor envy one another. Do not hate one another nor show enmity to one another. Be slaves of Allah, brothers, as you have been commanded to be. The Muslim is the brother of the Muslim. He does not wrong him nor disappoint him nor despise him. Godfearing is here," and he pointed to his chest. "It is enough evil for a man that he should despise his Muslim brother. The blood, honour and property of every Muslim is sacred to another Muslim. Allah does not look at your bodies nor your forms, but He looks at your hearts and your actions."
In one variant, "Do not envy one another nor hate one another nor spy nor pry nor bid against one another to raise the price and be slaves of Allah, brothers."
In one variant, "Do not cut one another off nor show enmity to one another. Do not hate one another nor envy one another. Be slaves of Allah, brothers.
In one variant, "Do not separate from one another nor should any of you sell against the sale of someone else." [Muslim has all of these variants and al-Bukhari has some.]
1571. Mu'awiya said, "I heard the Messenger of Allah, may Allah bless him and grant him peace, say, 'If you seek out the faults of the Muslims, you will corrupt them, or are about to corrupt them.'" [Abu Dawud]
1572. Ibn Mas'ud reported that a man was brought to him and it was said to him, "This is so-and-so and he has drops of wine on his beard." He said, "We were forbidden to pry, but if something is clear to us, then we punish for it." [Abu Dawud]