But he that shall endure unto the end, the same shall be saved.
Note 6 at Mt 24:13: Here Jesus was teaching that there is perseverance on the believer's part for complete salvation. Salvation is a gift that cannot be earned (Ro 6:23 and Eph 2:8-9) nor maintained (Ga 3:3 and Col 2:6) by the believer's own works. It has to be received by faith. However, there is effort on the believer's part to maintain that faith. This is where holiness comes in.
Holiness will not produce relationship with God, nor will a lack of holiness make God turn away from us. He deals with us according to our faith in Jesus and not our performance. But holiness will keep Satan from stealing our faith from us, while lack of holiness is an open invitation to the devil to do his worst. Those of us who want to endure to the end cannot live lifestyles that permit Satan free access to us.