I heard the Messenger of Allah ﷺ say, "Allah says, 'Son of Adam, do not fail to pray four units of prayer at the beginning of your day, and I will suffice you for the rest of it.'"
حدثنا داود بن رشيد حدثنا الوليد عن سعيد بن عبد العزيز عن مكحول عن كثير بن مرة أبي شجرة
سمعت رسول الله ﷺ يقول يقول الله عز وجل يا ابن آدم لا تعجزني من أربع ركعات في أول نهارك أكفك آخره
[Sahih] Ahmad narrated it, 5/287, from the hadith of Makhul, and Nasai in Kubra, no. 466, from the hadith of Kathir bin Mura through the same route, and Ibn Hibban graded it sahih, no. 634. The hadith has many corroborating narrations in Ahmad, 4/201, 153, and elsewhere.