I noticed recently a post on a social media site that a lady had written about one of her children being sick. There was a response in which the one posting said, "l love covenant children!" When I read the lady with the sick child's response to the comment, I was immediately filled with praise and thanksgiving to God! She responded, "Don't know if he's in the covenant of grace yet as he doesn't believe." God be thanked that He had given her understanding as to who the "covenant children" really are.
The children of the everlasting covenant are not the physical children of professing believers who sprinkle their babies and try to make that act the same as circumcision was under the old covenant. That old testament act was typical of a spiritual act which only the sovereign Spirit of God can perform. Paul says in Romans 2:29, "But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God." This does not come by an earthly birth but through being born again of the Spirit. This work of the Holy Spirit results in a revelation of Christ in us by His taking the things of Christ and showing them to us. Revealing to the sinner the things God has "freely given" to us through the crucified Christ. His blood is “ the blood of of the everlasting covenant.”
David, as a father and a believer, did not view his children in this connection according to the flesh. As a matter of fact, most of them did now show themselves to be covenant children but rather lost, wicked sinners. David said, “Although my house be not so with God, yet He hath made with ME an everlasting covenant, ordered in all things and sure and this all my salvation...” (2 Sam. 23:5) Although David by grace was the man after God’s own heart, that did not apply or transfer to any of his children naturally. Abraham likewise had a son who was not, Ishmael; but thankfully he had one who was, Isaac.
Grace does not run in blood lines! The covenant children are those God chose in Christ before the world began and sent His Son to die as their Substitute, putting away their sins. Christ alone is the Angel of the covenant and no covenant blessing is anyone’s apart from Him. All covenant children will be born of God and be enabled to believe the truth of Christ. Whether it is your child or mine, if they never know God in truth or believe on Christ, they aren’t and never were the covenant children!