Adam Clarke on 2 Samuel 24:24

Neither will I offer burnt-offerings - It is a maxim from heaven, "Honour the Lord with thy substance." He who has a religion that costs him nothing, has a religion that is worth nothing: nor will any man esteem the ordinances of God, if those ordinances cost him nothing. Had Araunah's noble offer been accepted, it would have been Araunah's sacrifice, not David's; nor would it have answered the end of turning away the displeasure of the Most High. It was David that sinned, not Araunah: therefore David must offer sacrifice, and at his own expense too.