And Saul built an altar unto the Lord
To offer peace offerings upon, in thankfulness for the victory obtained over his enemies, or sin offerings to make atonement for the sin of the people, perhaps both, however the former:
the same was the first altar that he built unto the Lord;
for though he had offered sacrifice at Gilgal, there was an altar ready built for him: or "he began to build"; he laid the first stone of it, and the builders built upon it; so some others say, that he was the first of the kings that built an altar to the Lord F4; others, the first of the judges that built one; though Gideon built one, it was for his own private use, not for all Israel, as this, so R. Isaiah; but Ben Gersom, and so Abarbinel, refer this to the great stone Saul ordered to be rolled to him, and take the sense to be, that that began to be built an altar to the Lord; that was the beginning of one; for he did not now stay to finish it, being eager on his pursuit of the Philistines, as follows.
F4 See Kimchi in loc.