Salvation depends on our believing. Religion says we must act our best. Salvation says we must accept God's best. Religion depends on the sufficiency of character. Salvation depends on the Sacrifice of the Cross.
Religion tries to furnish a sacrifice.
Salvation trusts in a finished sacrifice. Religion is striving for a better attainment. Salvation is secured through a perfect atonement. Religion tries to bring us from darkness to light. Salvation DOES bring us from Death unto Life.