For the life was manifested— Jesus Christ is here called the Life, not only as having life in himself, but as the author of eternal life, or that great and glorious Person, who revealed,and will bestow, that immortal glory and felicity, which was in former ages comparatively concealed in the breast or council of Deity; and which the Lord Jesus Christ so clearly manifested unto the apostles, and brought to light in the gospel. See John 1:4; John 11:25; John 14:6 and 1 John 5:11-12; 1 John 5:20. All this second verse ought evidently to be read in a parenthesis.
Related Commentaries of 1 John 1:2
1 John 1:2
2 (For the life was manifested, and we have seen it, and bear witness, and shew unto you that eternal life, which was with the Father, and was manifested unto us;)