ISB ~ John 16 v8

he will convince:The Spirit exposes the sin of unbelief for what it is (3:20), convinces the world that Christ, though condemned as a criminal, was truly righteous (8:46), and makes it known that Satan and every enemy of Christ will face judgment for rejecting him (5:26-29; 12:31; CCC 388, 1433). The mission of the Spirit, here described in juridical language, shows that while he acts as an advocate or defense lawyer for the disciples, he is also a prosecutor who indicts the unbelieving world.

See word study:Counselor at Jn 14.