We need life because in the sins and course of the world we were dead. 

Eph. 2:1“And you were dead in your trespasses and sins”

But this is not God’s desire for us (2 Pet. 3:19) and He has graciously provided for us a spiritual rebirth and renewal to bring us to live again. 

Eph. 2:4,5 “But God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved)”

The life God calls us to is provided through the work and teachings of Jesus Christ. 

Jn. 10:10 “I came that they might have life, and might have it abundantly.”

Jn. 6:35 “I am the bread of life…”
Jn. 14:6 “Jesus said to him, "I am the way, and the truth, and the life; no one comes to the Father, but through Me.”
And it is shared through the gospel. So the apostles were instructed:
Acts 5:20 “Go your way, stand and speak to the people in the temple the whole message of this Life”

So now Christ, the author of life, giver of the words of life, the way the truth and the life, the bread of life, is our life and we live our life in Him. 

Col. 3:4 “When Christ, who is our life, is revealed, then you also will be revealed with Him in glory.”
Gal. 2:20 “I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God…”