Matthew Henry Commentary 2 Samuel 24:18-25

"And Gad came that day to David, and said unto him, Go up, rear an altar unto Jehovah in the threshing-floor of Araunah the Jebusite. And David went up according to the saying of Gad, as Jehovah commanded. And Araunah looked forth, and saw the king and his servants coming on toward him: and Araunah went out, and bowed himself before the king with his face to the ground. And Araunah said, Wherefore is my lord the king come to his servant? And David said, To buy the threshing-floor of thee, to build an altar unto Jehovah, that the plague may be stayed from the people. And Araunah said unto David, Let my lord the king take and offer up what seemeth good unto him: behold, the oxen for the burnt-offering, and the threshing instruments and the yokes of the oxen for the wood: all this, O king, doth Araunah give unto the king. And Araunah said unto the king, Jehovah thy God accept thee. And the king said unto Araunah, Nay; but I will verily buy it of thee at a price. Neither will I offer burnt-offerings unto Jehovah my God which cost me nothing. So David bought the threshing-floor and the oxen for fifty shekels of silver. And David built there an altar unto Jehovah, and offered burnt-offerings and peace-offerings. So Jehovah was entreated for the land, and the plague was stayed from Israel." — 2 Samuel 24:18-25 (ASV)

God's encouraging us to offer spiritual sacrifices to him is evidence of his reconciling us to himself. David purchased the ground to build the altar. God hates robbery for burnt offering. Those do not know what religion is who are chiefly concerned with making it cheap and easy for themselves, and who are best pleased with what costs them the least effort or money.

For what purpose do we have our substance, if not to honour God with it; and how can it be better bestowed? Consider the building of the altar and the offering of proper sacrifices upon it. Burnt offerings to the glory of God's justice; peace offerings to the glory of his mercy.

Christ is our Altar, our Sacrifice; in him alone we may expect to escape his wrath and to find favour with God. Death is destroying all around, in so many forms and so suddenly, that it is madness not to expect and prepare for the close of life.