There is no doubt that our souls need to be saved. In addition, God has assured us that our salvation, by His grace, is already being accomplished and will continue to be accomplished through our faith in Christ. Having faith in Him assures us of the complete security of our salvation in all aspects.
While we are saved at rebirth, it is necessary for us to grow in grace, to mature in our faith, and to become fruitful to the glory of God. It is true that our soul was saved the moment we trusted Christ as our Savior, but we are sometimes prone to resist the work of the Holy Spirit, resulting in the fact that we remain in a state of spiritual infancy for the rest of our Christian lives.
Our eternal salvation is not dependent on what we do for God but on what Christ has done for us on the cross. Such sacrificial love calls for our complete and undivided love, not as a legalistic obligation but as our own, pure offering of love to the One who suffered for our sins, who was bruised for our follies, and who willingly bore the punishment on the cross.

Dear Heavenly Father, by faith in Christ's sacrificial work on the cross, I am a new creation in Christ and have received salvation - both now and in eternity to come. Thank You that the salvation of my body is equally secure, and I look forward to that glorious day when Christ comes to take us home to be with Him for all eternity. As we see Him as He is, we will become like Him. 
In Jesus's name I pray. Amen.