Because the Spirit Lives in You

But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you.  Romans 8:11 NASB
To make it clear, for a Christian there is no question as the “But if…” seems to indicate.  For the Christian, you should read the verse as, “Because the Spirit…”  You can have confidence in being resurrected from the dead to eternal life because God who has already done it with Christ promises to do the same with you.  And if you are confident that He is able to raise you to eternal life, then pray about what God wants you to do in this life, and do it.