Albert Barnes on John 16:1

These things. The things spoken in the two previous chapters, promising them divine aid and directing them in the path of duty.

Be offended. For the meaning of the word offend, Mt 5:29. It means here the same as to stumble or fall --that is to apostatize. He proceeds immediately to tell them, what he had often apprised them of, that they would be subject to great persecutions and trials. He was also himself about to be removed by death. They were to go into an unfriendly world. All these things were in themselves greatly fitted to shake their faith, and to expose them to the danger of apostasy. Comp. Lk 24:21. If they had not been apprise of this, if they had not known why Jesus was about to die, and if they had not been encouraged with the promised aid of the Holy Ghost, they would have sunk under these trials, and forsaken him and his cause. And we may learn hence,

1st. That if Christians were left to themselves they would fall away and perish.

2nd. That God affords means and helps beforehand to keep them in the path of duty.

3rd. That the instructions of the Bible and the help of the Holy Spirit are all granted to keep them from apostasy.

4th. That Jesus beforehand secured the fidelity and made certain the continuance in faith of his apostles, seeing all their danger and knowing all their enemies. And, in like manner, we should be persuaded that "he is able to keep that which we commit to him against that day," 2Ti 1:2, 12.