How do we know eternal life is real?

Eternal life is a core promise of the gospel, wherein Jesus, as stated in John 3:16, offers everlasting life to those who believe in Him. In 1 John 5:20, we know, 'We are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life.' The work of the Holy Spirit bears witness to this truth, imparting new life and faith to the believer. This assurance stems from Christ's resurrection, where He conquered sin and death, thus affirming the hope of eternal life for all who trust in Him.