John Gill Commentary 2 Chronicles 15:11

"And they sacrificed unto Jehovah in that day, of the spoil which they had brought, seven hundred oxen and seven thousand sheep." — 2 Chronicles 15:11 (ASV)

And they offered unto the Lord the same time
The Targum adds, on the feast of weeks, or Pentecost: of the spoil which they had brought; from the camp of the Ethiopians, and the cities of the Philistines:

seven hundred oxen and seven thousand sheep ;
partly for burnt offerings, and partly for peace offerings, by way of thankfulness to the Lord for the victory he had given them, and for a feast at the making of the following covenant with him.