Luther’s teaching: his Augsburg Confession professes men to be born with
sin, that is, without the fear of God, without trust in God, and with
concupiscence; and that this disease, or vice of origin, is truly sin,
even now condemning and bringing eternal death upon those
not born again through Baptism and the Holy Ghost. concupiscence
is of itself sinful, and being the sinful corruption of human nature
caused by Adam’s transgression and inherited by all his
descendants, is the very essence of original sin.
Biblical argument: 
2 Corinthians 4:3-4 And even though our gospel is veiled, it is
veiled for those who are perishing, in whose case the god of this
age has blinded the minds of the unbelievers, so that they may
not see the light of the gospel of the glory of Christ, who is the
image of God.
Hebrews 2:14 Now since the children share in blood and flesh,
he likewise shared in them, that through death he might destroy
the one who has the power of death, that is, the devil,  and free
those who through fear of death had been subject to slavery all
their life.