2 Corinthians 2:17

For we are not as the many, corrupting the word of God: but as of God, in the sight of God, speak we in Christ.

Corrupting the word of God ... The figure here is originally that of a tavern keeper who mixes poor wine with good to increase his profits."[16] In such a comparison as this, two things appear: (1) there is the disclosure of the true motive of false teachers who are in the gospel business for the profit they can make for themselves, and (2) there is the usual method of such teachers, that of adding to the gospel substances that are no part of the true gospel with the intention of making it more acceptable to sinners who rebel at the true gospel.

As Carver said of this:

The first leads to the second. To approach the ministry with motives of personal profit, ambition, or vanity, is already to adulterate it. He who makes the word serve his advantage rather than being a servant of the word changes the very character of the gospel.[17]

Paul's quadruple affirmation of the integrity of his own ministry is the profound declaration that it was conducted: (1) in sincerity, (2) of God, that is, by his direct authority and order, (3) in the sight of God, that is, openly and in view of all people as well as in the sight of God, and (4) in Christ, which means, as a pure and faithful member of the spiritual body of Christ (the church), and in full compliance with all Christian duties.

[16] Ibid.

[17] Ibid.