The Prophet ﷺ said, "The son of Adam has been allotted his share of fornication, which he will inevitably encounter. The fornication of the eyes is looking, the fornication of the ears is listening, the fornication of the tongue is speech, the fornication of the hand is grasping, and the fornication of the foot is walking. The heart desires and longs, and the private parts either confirm all that or deny it."
عن النبي ﷺ قال: كتب على ابن آدم نصيبه من الزنى، مدرك ذلك لا محالة، فالعينان زناهما النظر، والأذنان زناهما الاستماع، واللسان زناه الكلام، واليد زناها البطش، والرجل زناها الخطا، والقلب يهوى، ويتمنى، ويصدق ذلك الفرج، ويكذبه.
Muslim narrated it in the Chapter on Divine Decree (21:2657), from Ishaq bin Mansur, who said, Abu Hisham Makhzumi informed us, who said, Wahib told us, who said, Suhayl bin Abu Salih told us, from his father, from Abu Hurairah, and he mentioned it.Abu Dawud also narrated it (2152) through another route, from Hammad, from Suhayl bin Abu Salih with his chain, adding to it, "and the mouth commits fornication, its fornication being kissing." Its chain is hasan.His saying, "and guard their private parts" [Nur 24:31]