John 15:6:

If a man abide not in me, he is cast forth as a branch, and is withered; and men gather them, and cast them into the fire, and they are burned.

See also:

Objection: Isaiah 53:4 (Matthew 8:17) Was Fulfilled in Jesus’ Earth Ministry and Cannot be Claimed as a Promise by Christians Today
Objection: Healing Cannot Be in the Atonement Because Healing Can Be Lost, But Salvation Cannot Be Lost