How does Christ's prayer in John 17 affirm the security of salvation?

Jesus's prayer in John 17 is a remarkable testimony to the security of salvation for believers. When He states that 'none of them is lost' (John 17:12), He assures us of the effectiveness of His redemptive work and the power of His intercession. This underscores the truth that once a person is chosen by God and awakened to faith, they cannot fall away from grace. The assurance of being kept by Christ highlights the active work of the Holy Spirit who sustains and nurtures the believer's faith. This cannot hinge on human effort, but rests firmly in the faithfulness of Christ who prosecutes His covenant promises to keep His own, shining light on the depths of God's love and commitment to His people.