Hadithcore
Hadith #517870

Malik related to me that he heard that Umar ibn al-Khattab went to the villages every Saturday. If he found a slave doing work which he was not capable of doing, he lightened it for him.

وَحَدَّثَنِي مَالِكٌ، أَنَّهُ بَلَغَهُ أَنَّ عُمَرَ بْنَ الْخَطَّابِ، كَانَ يَذْهَبُ إِلَى الْعَوَالِي كُلَّ يَوْمِ سَبْتٍ فَإِذَا وَجَدَ عَبْدًا فِي عَمَلٍ لاَ يُطِيقُهُ وَضَعَ عَنْهُ مِنْهُ ‏.‏

References2 variants
Sunnah.com reference
Book 54, Hadith 42
Arabic/English book reference
Book 54, Hadith 41