How do we know that preservation in Christ is true?

The doctrine of preservation in Christ is grounded in Scripture, particularly highlighted in verses like 1 John 2:19, which indicates that those who leave the faith were never truly of us. True believers are kept by the power of God through faith, as stated in 1 Peter 1:5. This suggests that believers are securely preserved in their salvation not because of their own works but due to the sustaining power of Christ. Therefore, the assurance of perseverance is rooted in God's faithfulness to His elect, ensuring that they will not fall away from His grace.