The Lord thy God - There is an implied censure of Samuel in this phrase. Saul says that Samuel blames him for what was done in honor of Samuel’s God; as if be had more zeal for the glory of God than was felt by Samuel.
Related Commentaries of 1 Samuel 15:21
1 Samuel 15:21
21 But the people took of the spoil, sheep and oxen, the chief of the things which should have been utterly destroyed, to sacrifice unto the LORD thy God in Gilgal.