Riyad as-Salihin

Abu Hurairah (May Allah be pleased with him) reported: I heard Messenger of Allah (ﷺ) saying, "Whosoever visits an ailing person or a brother of his to seek the Pleasure of Allah, an announcer (angel) calls out: 'May you be happy, may your walking be blessed, and may you be awarded a dignified position in Jannah".

[At- Tirmidhi, who categorized it as Hadith Hasan].