John Calvin Commentary 1 John 1:2

"(and the life was manifested, and we have seen, and bear witness, and declare unto you the life, the eternal [life], which was with the Father, and was manifested unto us);" — 1 John 1:2 (ASV)

For (or, and) the life was manifested. The conjunction is explanatory, as though he had said, “We testify of the life-giving Word, as life has been manifested.” The sense can at the same time be twofold: that Christ, who is life and the fountain of life, has been manifested, or that life has been openly offered to us in Christ. The latter, indeed, necessarily follows from the former. Yet regarding the meaning, the two things differ, as cause and effect. When he repeats, We show, or announce eternal life, he speaks, I have no doubt, of the effect: namely, that he announces that life is obtained for us in Christ.

From this we learn that when Christ is preached to us, the kingdom of heaven is opened to us, so that, being raised from death, we may live the life of God.

Which was with the Father. This is true not only from the time when the world was formed but also from eternity, for he was always God, the fountain of life. His eternal wisdom possessed the power and ability to give life.

However, he did not actually exercise this before the creation of the world. From the time when God began to reveal the Word, that power, which was previously hidden, spread over all created things.

Some manifestation had already been made; the Apostle had something else in view: namely, that life was finally manifested in Christ when he, in our flesh, completed the work of redemption. For though the fathers, even under the law, were associates and partakers of the same life, yet we know that they were kept in expectation of the hope that was to be revealed.

It was necessary for them to seek life from the death and resurrection of Christ. However, the event was not only far distant from their sight but also hidden from their minds. They depended, then, on the hope of revelation, which finally came in due time. Indeed, they could not have obtained life unless it was manifested to them in some way. But the difference between us and them is that we hold him already revealed, as it were, in our hands, while they sought him who was obscurely promised to them in types.

But the Apostle's aim is to remove the idea of novelty, which might have lessened the dignity of the Gospel. He therefore says that life had not just then begun to exist, though it had only recently appeared, because it was always with the Father.