Rom 5:
15But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many.
16And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offences unto justification.
Christ sacrifice as the Lamb of God, did not just take away the sin of adam that brought condemnation, but it also went far beyond, and expiated the sins or the personal transgressions of all who initially sinned in Adam.
So the sin of the world in Jn 1 29 includes the many offences of the many as well..
He took away all the legal condemnation that sin brought unto those Christ died for. Col 2:
14Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;
Any sin they committed against God's Law, whether in Adam, or actually in themselves, that was contrary to them, or could be legally laid to their charge, Christ took away the legal condemnation because all of it was nailed to His Cross..
