This is the first and most important message to us from God's word. The Gospel. 

Mark 16:15

He said to them, “Go into all the world and preach the gospel to all creation.

For the wages of sin is death, but the free gift of God is eternal life through Christ Jesus our Lord.

“For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.

But God shows his love for us in that while we were still sinners, Christ died for us.

He saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit,

But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved— and raised us up with him and seated us with him in the heavenly places in Christ Jesus, so that in the coming ages he might show the immeasurable riches of his grace in kindness toward us in Christ Jesus. For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,

Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him.

But to all who did receive him, who believed in his name, he gave the right to become children of God,

So faith comes from hearing, and hearing through the word of Christ.

I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel— not that there is another one, but there are some who trouble you and want to distort the gospel of Christ. But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed. As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.

I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me.

Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.