“Bad human will” is a separation from a divine will.
In other words, sin, because sin is anything which goes against God's will. And we are told why Jesus came to the world:
“This is a faithful saying and worthy of all acceptance, that
Christ Jesus came into the world to save sinners, of whom I am chief.” (1Ti 1:15 NKJV)
And it is as sinners that Jesus saves us:
“For Christ also suffered once for sins,
the just for the unjust, that He might bring us to God, being put to death in the flesh but made alive by the Spirit,” (1Pe 3:18 NKJV)
By nature, we all have "bad human wills." We are all sinners. We all need a Saviour. God would be waiting forever if we hd to become good before believing in Jesus Christ and being saved.
“6 ¶ For when we were still without strength, in due time
Christ died for the ungodly. 7 For scarcely for a righteous man will one die; yet perhaps for a good man someone would even dare to die. 8
But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us.” (Ro 5:6-8 NKJV)