John 16:9 - Ellicott's Commentary On The Whole Bible

Of sin, because they believe not on me. — This should not be interpreted, as it very frequently is, of the sin of unbelief, but of sin generally; unbelief in Christ is stated as the cause of sin. Sin is missing the aim of life, the disordered action of powers that have lost their controlling principle. Christ is the revelation to the world of the Father’s love. In union with God through Him the soul finds the centre of its being, and the true purpose of its life. By the witness of Christ the Holy Spirit convinces men that He is the centre of the moral harmony of the Universe, and that through Him their spirits have access to God. This conviction reveals to them their sin, because they believe not on Him. Its effect is salutary or condemnatory, according as we are convinced and converted by it, or refuse its influence and remain convicted.