John Gills Exposition of the Bible Commentary - 2 Samuel 24:21
And Araunah said, wherefore is my lord the king come to his servant ?.... Which both implies admiration in him, that so great a person should visit him in his threshingfloor; that a king should come to a subject his servant, who should rather have come to him, and would upon the least intimation; it was a piece of condescension he marvelled at; and it expresses a desire to know his pleasure with him, supposing it must be something very urgent and important, that the king should come himself... read more
Matthew Henry's Complete Commentary - 2 Samuel 24:18-25
Here is, I. A command sent to David to erect an altar in the place where he saw the angel, 2 Sam. 24:18. This was to intimate to David, 1. That, upon his repeated submission and humiliation, God was now thoroughly reconciled to him; for, if the Lord had been pleased to kill him, he would not have accepted an offering, and therefore would not have ordered him to build an altar. God's encouraging us to offer to him spiritual sacrifices is a comfortable evidence of his reconciling us to himself.... read more