Salvation is what God does for man. Religion says, Something in my hand I bring. Salvation says, Nothing in my hand I bring. Religion is trusting in a work we do. Salvation is trusting in a work that has been done.
Religion depends on our behaving.
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.