But the people took of the spoil, sheep and cattle, the best of the devoted things, to sacrifice to Yahweh your God in Gilgal.” Bible

“But the people.” Here Saul shifts the blame for not fulfilling the word of Yahweh from himself to the people, but even so he does not admit that what happened was wrong or disobedient. He is just acting as if instead of killing the animals where they were in the camps of the Amalekites, he was bringing them back to Israel to sacrifice them.

“to sacrifice to Yahweh your God in Gilgal.” Saul is making it seem like he is fulfilling the word of Yahweh, but not wanting to do it where the Amalekites were, he wanted to complete the sacrifice in Gilgal, which had a long sacred history. But it seems clear that Saul is just making things up as he goes.

Commentary for: 1 Samuel 15:21