1 Corinthians 15:17:
And if Christ be not raised, your faith is vain; ye are yet in your sins.
I believe Christ was raised from the dead and bodily ascended into heaven. I believe the biblical & historical accounts, as well as the faith of the fathers throughout the generations. The evidence has convinced me that Christianity is the true faith, and that the Lord Jesus alone has the power to present me faultless to God. I’ve also seen evidence that Christ has is doing a work within me, which is called sanctification. This further convinces me that my faith in Christ is justified.
But what if Christ was not God’s only son, and is not the way to approach the father? If so, then I’m yet in my sins and lost. That means either there is no God, or that I’ve chosen the wrong faith. But either way, if I don’t believe, then I’m lost. What a horrible place to be.
I’ve chosen (or God has chosen for me) to believe that Christ the God-man walked with humanity, taught, healed, performed miracles, and ultimately died while taking God’s wrath in my place. Is my faith in vain? I think not.