Albert Barnes Commentary 2 Corinthians 1:21

"Now he that establisheth us with you in Christ, and anointed us, is God;" — 2 Corinthians 1:21 (ASV)

Now He who establishes us. He who makes us firm (o bebaiwn hmav); that is, He who has confirmed us in the hopes of the gospel, and who gives us grace to be faithful, and them in our promises. The object of this is to trace all to God and to prevent the appearance of self-confidence or of boasting. Paul had spoken at length on his own fidelity and veracity. He had taken pains to prove that he was not inconstant and fickle-minded. He here says that this was not to be traced to himself, or to any native goodness, but was all to be traced to God. It was God who had given them all confident hope in Christ; and it was God who had given him grace to adhere to his promises and to maintain a character for veracity. The first "us" in this verse probably refers to Paul himself; the second also includes the Corinthians, as they too are anointed and sealed.

And hath anointed us. Us who are Christians. It was customary to anoint kings, prophets, and priests upon entering their office, as a part of the ceremony of inauguration. The word anoint is applied to a priest, Exodus 28:41 and Exodus 40:15; to a prophet, 1 Kings 19:16 and Isaiah 61:1; to a king, 1 Samuel 10:1, 1 Samuel 15:1, 2 Samuel 2:4, and 1 Kings 1:34.

It is applied often to the Messiah as being set apart or consecrated to His office as prophet, priest, and king—that is, as appointed by God to the highest office ever held in the world. It is applied also to Christians as being consecrated or set apart to the service of God by the Holy Spirit—a use of the word that is derived from the sense of consecrating, or setting apart, to the service of God.

Thus in 1 John 2:20, it is said, But we have an unction from the Holy One, and know all things. So in 1 John 2:27, But the anointing which ye have received abideth in you, etc. The anointing that was used in the consecration of prophets, priests, and kings seems to have been designed to be emblematic of the influences of the Holy Spirit, who is often represented as poured upon those who are under His influence (Proverbs 1:23; Isaiah 44:3; Joel 2:28–29; Zechariah 12:10; Acts 10:45), in the same way as water or oil is poured out. And as Christians are everywhere represented as being under the influence of the Holy Spirit, as being those on whom the Holy Spirit is poured, they are represented as "anointed." They are in this manner solemnly set apart and consecrated to the service of God.

Is God. God has done it. All is to be traced to Him. It is not by any native goodness that we have, or any inclination that we have by nature to His service. This is one of the instances that abound so much in the writings of Paul, where he delights to trace all good influences to God.