Abu Uthman an-Nahdi said: Abu Musa wrote to a Persian leader and greeted him with peace in his letter. He was asked, “Do you greet him with peace when he is a disbeliever?” He replied, “Indeed, he wrote to me and greeted me with peace, so I have answered him.”
[Bukhari, Al-Adab Al-Mufrad #1101]
عَنْ أَبِي عُثْمَانَ النَّهْدِيِّ قَالَ: كَتَبَ أَبُو مُوسَى إِلَى رُهْبَانٍ يُسَلِّمُ عَلَيْهِ فِي كِتَابِهِ، فَقِيلَ لَهُ: أَتُسَلِّمُ عَلَيْهِ وَهُوَ كَافِرٌ؟ قَالَ: إِنَّهُ
And give to the orphans their properties and do not substitute the defective [of your own] for the good [of theirs]. And do not consume their properties into your own. Indeed, that is ever a great sin. Surah An-Nisā’ (4:2)
Abu Huraira(RA) reported Allah’s Messenger (may peace be upon him) as saying. Allah fixed the very portion of adultery which a man will indulge in. There would be no escape from it. The adultery of the eye is the lustful look and the adultery of the ears is listening to voluptuous (song or talk) and the adultery of the tongue is licentious speech and the adultery of the hand is the lustful grip (embrace) and the adultery of the feet is to walk (to the place) where he intends to commit adultery and the heart yearns and desires which he may or may not put into effect.(MusliM,Book 33 Hadith 6422)
Narrated AbudDarda’: The Prophet (peace_be_upon_him) said: the similitude of a man who emancipates a slave at the time of his death is like that of a man who gives a present after satisfying his appetite. [Abu Dawud 024:3957]