How do we know that salvation in Christ is certain?

Salvation is certain because it is rooted in the sovereignty of God, particularly as seen in Romans 8:29-30, where Paul outlines the divine purpose of those God foreknew. The certainty of salvation does not depend upon human effort or decision but on God's will and grace. Christ's prayer in John 17:2, where He requests eternal life for those given to Him by the Father, shows that this promise is secured by His authority and will. Hebrews 10:14 reinforces this certainty by proclaiming that by one sacrifice, He has perfected forever those who are being sanctified. Therefore, true believers can have assurance that their salvation is secure in Christ's accomplished work.