Jeremiah 2:19 English Standard Version (ESV) Your evil will chastise you, and your apostasy will reprove you. Know and see that it is evil and bitter for you to forsake the Lord your God; the fear of me is not in you, declares the Lord God of hosts.

Apostasy is a falling away in a relationship with our Lord, forsaking our Lord.

Hosea 14:4 English Standard Version (ESV) I will heal their apostasy;  I will love them freely, for my anger has turned from them.

The cure for any damaged relationship is love and mercy.

Jesus likened it to love running cold.

Matthew 24:11-12 English Standard Version

11 And many false prophets will arise and lead many astray. 12 And because lawlessness will be increased, the love of many will grow cold.

The priest accused Paul of being an apostate because he was teaching Christ in the synagogues, saying he had fallen away from the Jewish faith. In many ways these false prophets and teachers Jesus warns us about are trying to get the faithful to cling to knowledge and forsake our relationship with the Lord.

The only protection from false prophets and teachers is a close personal relationship with the Lord.

1 Timothy 4:1-2 English Standard Version

1 Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons, 2 through the insincerity of liars whose consciences are seared,

The list of insincere lies remains unsaid here because the list is much longer today. The stronger our faith is, the more cunning the lies of the enemy become. Be careful who we listen to these days.