John Calvin Commentary 2 Thessalonians 1:10

"when he shall come to be glorified in his saints, and to be marvelled at in all them that believed (because our testimony unto you was believed) in that day." — 2 Thessalonians 1:10 (ASV)

When he shall come to be sanctified. As he has until now discussed the punishment of the wicked, he now returns to the pious, and says that Christ will come, that he may be glorified in them; that is, that he may irradiate them with his glory, and that they may be partakers of it.

“Christ will not have this glory for himself individually; but it will be common to all the saints.” This is the crowning and choice consolation of the pious, that when the Son of God will be manifested in the glory of his kingdom, he will gather them into the same fellowship with himself.

There is, however, an implied contrast between the present condition in which believers labor and groan, and that final restoration. For they are now exposed to the reproaches of the world, and are looked upon as vile and worthless; but then they will be precious, and full of dignity, when Christ will pour forth his glory upon them.

The purpose of this is that the pious may, as it were, with closed eyes, pursue the brief journey of this earthly life, having their minds always intent upon the future manifestation of Christ’s kingdom. For to what purpose does he make mention of his coming in power, but that they may in hope leap forward to that blessed resurrection which is still hidden?

It should also be observed that after using the term saints, he adds, by way of explanation—those that believe. By this he intimates that there is no holiness in humans without faith, but that all are profane. Finally, he again repeats the term—in that day, because that expression is connected with this sentence. He repeats it for this reason: to restrain the desires of believers, lest they rush ahead beyond proper limits.

Because credit was given. What he had said in a general way concerning saints, he now applies to the Thessalonians, that they may not doubt that they are of that number.

“Because,” he says, “my preaching has obtained credit among you, Christ has already enrolled you in the number of his own people, whom he will make partakers of his glory.”

He calls his doctrine a testimony, because the Apostles are Christ’s witnesses (Acts 1:8). Let us learn, therefore, that the promises of God are ratified in us when they gain credit with us.