Exactly! By why didn't they believe the Truth?
John 9
39 And Jesus said, For judgment I am come into this world,
that they who see not might see;
and that they WHO SEE might be made blind.
40 And some of the Pharisees who were with him heard these words,
and said unto him, Are we blind also?
41 Jesus said unto them, If you were blind,
you should have no sin: but now you say,
WE SEE; therefore your sin remains.
Matthew 3
7 But when he saw many of the Pharisees and Sadducees
come to his baptism, he [John] said unto them,
O generation of vipers, who has warned you to flee
from the wrath to come?
8 Bring forth therefore fruits befitting for repentance:
Romans 2:4 Or despise you the riches of his goodness
and forbearance and longsuffering; not knowing that the goodness
of God leads you to repentance?
What if God, willing to show his wrath, and to make his power known,
endured with much longsuffering the vessels of wrath fitted to destruction:
2 Timothy 2
20 But in a great house there are not only vessels of gold and of silver,
but also of wood and of earth; and some to honor, and some to dishonor.
21If a man therefore purge himself from these,
he shall be a vessel unto honor, sanctified,
and fit for the master's use, and prepared unto every good work.
25In meekness instructing those that oppose them;
if God perhaps will give them repentance to the acknowledging of the truth;
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I'm sure that's not all the scriptural evidence there is on this subject, but I don't think anyone would disagree that God must grant people the ability to purge themselves [to see and to repent].