The phrase "mortal body" refers to the physical body that all humans have, which is susceptible to aging, sickness, and eventually death. Full definition
Our «faith in Christ Jesus» (Col. 1:5) is our way of articulating faith in God, out of the conviction that God has revealed, in Christ, the perfect pattern of faith and that «he who raised Christ Jesus from the dead will give life to [our] mortal bodies also through his Spirit which dwells in [us]» (Rom. (religion-online.org)
Thankfully, God sent us His Son, Jesus to die for our sins so that when these sinful, mortal bodies die, we may have eternal life with Him. (religion.blogs.cnn.com)