21:1-30 David's numbering the people. - No mention is made in this book of David's sin in the matter of Uriah, neither of the troubles that followed it: they had no needful connexion with the subjects here noted. But David's sin, in numbering the people, is related: in the atonement made for that sin, there was notice of the place on which the temple should be built. The command to David to build an altar, was a blessed token of reconciliation. God testified his acceptance of David's offerings on this altar. Thus Christ was made sin, and a curse for us; it pleased the Lord to bruise him, that through him, God might be to us, not a consuming Fire, but a reconciled God. It is good to continue attendance on those ordinances in which we have experienced the tokens of God's presence, and have found that he is with us of a truth. Here God graciously met me, therefore I will still expect to meet him.
1Ch 21:18-30. He Builds an Altar.
18. the angel of the Lord commanded Gad to say—The order about the erection of an altar, as well as the indication of its site, is described (2Sa 24:18) as brought directly by Gad. Here we are informed of the quarter whence the prophet got his commission. It is only in the later stages of Israel's history that we find angels employed in communicating the divine will to the prophets.