The Messenger of Allah ﷺ said, "When one of you loves his brother, let him tell him that he loves him."
قال رسول الله ﷺ: إذا أحب أحدكم أخاه فليخبره أنه يحبه.
Abu Dawud (5124), Tirmidhi (2392), and Ahmad (17171) all narrated it, and Ibn Hibban (507) graded it sahih, all of them through Yahya bin Saeed Qattan, who said, Thawr bin Yazid narrated to us, who said, Habib bin Ubayd narrated to me, from Miqdam bin Mad Yakrib, and he related it. Its isnad is sahih.Tirmidhi said, "Hasan sahih gharib, and Miqdam's kunya was Abu Kareemah."