True. This is the reason the Day of Judgement has not arrived yet.
But this is a general provision that affects the whole world.
It is not suggesting that when people hear the Gospel they can afford to put off their decision to whenever they wish. Further, those who harden their hearts may discover that God leaves them in this hard-hearted condition permanently. A person cannot come to God whenever he or she chooses. Such a flippant attitude toward the dire nature of judgment will certainly lead to destruction.
Proverbs 29:1 NKJV
He, that being often reproved hardeneth his neck, shall suddenly be destroyed, and that without remedy.
No one knows the day Christ will return, and no one knows with certainty the day of their death.
2 Corinthians 6:2 NKJV
For He says:
“In an acceptable time I have heard you,
And in the day of salvation I have helped you.”
Behold, now is the accepted time; behold, now is the day of salvation.
Thus the warning not to harden our hearts. Salvation is freely available to all, but not all will receive it. The greatest danger is not to those who vehemently oppose the message (like Saul of Tarsus), but to those who say, “Maybe later”.
So true.