Hazrath Abu Huraira Radhiallahu Anhu narrated that:

The Prophet (ﷺ) said, "Religion is very easy and whoever overburdens himself in his religion will not be able to continue in that way. So you should not be extremists, but try to be near to perfection and receive the good tidings that you will be rewarded; and gain strength by worshiping in the mornings, the afternoons, and during the last hours of the nights." (See Fath-ul-Bari, Page 102, Vol 1).

Reference : Sahih al-Bukhari 39
In-book reference : Book 2, Hadith 32