This verse explains the significance of Jesus' death on the cross. In this verse, we are reminded that Jesus' death on the cross is the key to eternal life, and that belief in Him is a requirement for salvation. A parallel is drawn between the lifting up of the serpent in the wilderness and Jesus' death on the cross, emphasizing being lifted up as a symbol of salvation and Jesus as the ultimate savior.
Nicodemus knew that God, in His grace and justice, answered Moses' intercession on behalf of the Israelites by instructing him to lift up a brass serpent on a pole in the wilderness as a substitute for their sins. Through faith and grace, all who looked upon the brass serpent of judgement were saved.
Neither self-effort, extensive training, mortification, or ignoring the presence of sin in our lives will result in us being forgiven of our sins and having our lives redeemed from death. The only way to be saved is by looking at the perfect sacrifice for sin that God has provided, Jesus Christ. He is our sin substitute, Who was lifted up on the Cross for the salvation of all who would look on Him by faith.

Dear Heavenly Father, thank You for the truth that just as Moses lifted up the serpent in the wilderness, so Your Son Jesus must be lifted up on the cross. I believe in Him and that I have eternal life through Him. May I always remember that Jesus' death on the cross is the ultimate sacrifice for my sins and the only way to salvation. I pray that my faith in Him continues to grow stronger, and that I may live a life that honors Him.
In Jesus's name I pray. Amen.