26 But when the Counselor comes, whom I shall send to you from the Father, even the Spirit of truth, who proceeds from the Father, he will bear witness to me;

Matthew Henry's Commentary on John 15:26

Commentary on John 15:26-27

(Read John 15:26-27)

The blessed Spirit will maintain the cause of Christ in the world, notwithstanding the opposition it meets with. Believers taught and encouraged by his influences, would bear testimony to Christ and his salvation.