We know we are saved through our faith in the gospel and the assurance of the Holy Spirit who abides in us.
The assurance of salvation comes from recognizing that those who believe in the gospel possess eternal life. In 1 John 5:9-12, it is made clear that he who has the Son has life. The internal testimony of the Holy Spirit, referred to as the 'unction,' confirms this truth within the believer. True belief responds to the gospel, which assures us that Jesus' perfect work on the cross secures our salvation. This confidence does not rest in our performance but in the completed work of Christ and the transformative power of God in our lives.
Scripture References:
1 John 5:9-12, 1 John 3:19-20, Romans 5:1-2, Romans 8:16, Romans 8:38-39
Commentary