2 Samuel 24:24 "But the king replied to Araunah, 'No, I insist on paying for it. I will not sacrifice to the Lord my God burnt offerings that cost me nothing."
The text is David's purchasing the threshing floor of Araunah, even after Araunah offered it free to the king. David, who knew his sinfulness, was ready to sacrifice for God. If ministry costs you something today, that's okay — God and His work are worth it. Give Him all you have to give.