In the Old Testament of the Holy Bible, the LORD God judges unbelief in Him.  Many times over.

Unbelief was judged by the living God.
(NASB) 1 Kings 18:40 “Then Elijah said to them, ‘Seize the prophets of Baal; do not let one of them escape.’  So they seized them; and Elijah brought them down (from the top of Mount Carmel) to the brook Kishon, and slew them there.”

450 prophets of Baal were put to death because they had no belief in the living God.

Radical actions of judgment.  They could have turned to the living God when they saw Him use fire to consume a sacrifice soaked in water.  1 Kings 18:30-39

Elijah was doing what the LORD commanded Moses in the book of Deuteronomy.

Any prophet is put to death because he counseled rebellion against the LORD your God.  The living God brought the sons of Israel from slavery in Egypt, many hundreds of years before.  This same God redeemed this people from the house of slavery of sin.  Idolatry is sin against God.

God is the just God who judges unbelief.

Idolatry is sin… God says so.
God judges unbelief in Him… and it is for eternity.

“Take care, brethren,
that there not be in any one of you an evil, unbelieving heart
that falls away from the living God.”
(NASB) Hebrews 3:12

~ Take it to heart ~

“What must I do to be saved?” 
(NASB) Acts 4:12 “And there is salvation in no one else; for there is no other name (the name of Jesus) under heaven that has been given among men by which we must be saved.”

Receive the Lord Jesus as your Savior… He alone is accepted by the living God to take away your sins.

Follower of Christ… never get over what Jesus did for you!
(NASB) Philippians 2:8-11 “Being found in appearance as a man, He (Jesus) humbled Himself by becoming obedient to the point of death, even death on a cross.
9 For this reason also, God highly exalted Him, and bestowed on Him the name which is above every name,
10 so that at the name of Jesus EVERY KNEE WILL BOW, of those who are in heaven and on earth and under the earth,
11 and that every tongue will confess that Jesus Christ is Lord, to the glory of God the Father.”