Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "A slave becomes nearest to his Rubb when he is in prostration. So increase supplications while prostrating."[Muslim]. (RU)
App reference (RU): Book 16, Hadith 21 (RU)
Arabic/English book reference (RU): Book 16, Hadith 1428 (RU)