From Sahih Muslim (Hadith 6830):
Abu Huraira reported Allah's Apostle (ﷺ) as saying that Allah, the Exalted and Glorious, said:When My servant draws close to Me by the span of a palm, I draw close to him by the cubit and when he draws close to Me by the cubit, I draw close to him by the space (covered) by two armspans, and when he comes to me walking, I go in a hurry towards him
Reference: Muslim 6830