[American Constitutionalist]

In the day of the Lord, yes, they will try to seek and approach God, but, not in the only way God has provided, they will continue to reject the ONLY way of salvation that is JESUS CHRIST.
Yes, they will go to their churches or Synagogues and act all spiritual, and try to reform themselves, but GOD won't hear them.
God won't hear them because they have rejected the Messiah, Jesus Christ our Lord.

[The Ignorant Fisherman]

Yes that is true, though there will be MANY saved at this time (Day of the Lord)as Rev 7:9-17 states, but at the end of the night time part of the Day of the Lord (the 7 year tribulation)those who have known him will enjoy the day time part of the Day of the Lord -the 1000 year reign of Messiah and those who rejected salvation; ETERNAL damnation Matt. 25:31-46.