If the first question and answer of the Westminster shorter catechism is correct, that the chief end of man is to glorify God and enjoy Him forever.
If Adam and Eve had been created in the garden and had not sinned they would have been promised eternal life. But human beings would not be that much different than the angels. They would praise God for being the creator, but we have to understand that, God is perfect and God deserves all the praises he can get, to get the most praise from His people he has created, sin would have to come into the world and God would need a plan to save those sinners.
It says in Hebrews 12:2 that Jesus is the author of our faith. There is no other way for a just God to save sinners than for Jesus to die to pay for the sins of all those that the Trinity had planned to save. And Jesus is the finisher of our faith, if sin entered the world there would only be one possible way for God to save those people. Jesus would have to satisfy the wrath of God against all the people that he had planned to save.
So if the second person of the Trinity offered to pay for our sins, then He could rightly be called the author of our faith.
Hebrews 12:2 says, “Who for the joy that was set before Him, endured the cross, despising eh shame, and sat down at the right hand of the throne of God.”