These things I have spoken unto you, that in me ye might have peace. In the world ye shall have tribulation: but be of good cheer; I have overcome the world. That in me ye might have peace - I give you this warning as another proof that I know all things, and to the end that ye may look to me alone for peace and happiness. The peace of God is ever to be understood as including all possible blessedness - light, strength, comfort, support, a sense of the Divine favor, unction of the Holy Spirit, purification of heart, etc., etc., and all these to be enjoyed in Christ.
In the world ye shall have tribulation - Or, as most of the very best MSS. read, εχετε, ye have - the tribulation is at hand; ye are just about to be plunged into it.
But be of good cheer - Do not despond on account of what I have said: the world shall not be able to overcome you, how severely soever it may try you.
I have overcome the world - I am just now going by my death to put it and its god to the rout.
My apparent weakness shall be my victory; my ignominy shall be my glory; and the victory which the world, the devil, and my adversaries in general, shall appear to gain over me, shall be their own lasting defeat, and my eternal triumph. - Fear not!
Luther writing to Philip Melancthon, quotes this verse, and adds these remarkable words: "Such a saying as this is worthy to be carried from Rome to Jerusalem upon one's knees."
One of the grand subjects in this chapter, the mediation of Christ, is but little understood by most Christians. Christ having made an atonement for the sin of the world, has ascended to the right hand of the Father, and there he appears in the presence of God for us. In approaching the throne of grace, we keep Jesus as our sacrificial victim, continually in view: our prayers should be directed through him to the Father; and, under the conviction that his passion and death have purchased every possible blessing for us, we should, with humble confidence, ask the blessings we need; and, as in him the Father is ever well pleased, we should most confidently expect the blessings he has purchased. We may consider, also, that his appearance before the throne, in his sacrificial character, constitutes the great principle of mediation or intercession. He has taken our nature into heaven; in that he appears before the throne: this, without a voice, speaks loudly for the sinful race of Adam, for whom it was assumed, and on whose account it was sacrificed. On these grounds every penitent and every believing soul may ask and receive, and their joy be complete. By the sacrifice of Christ we approach God; through the mediation of Christ God comes down to man.
Commentary on the Bible, by Adam Clarke [1831].