Believe on the Lord Jesus and you will be saved-and your house. Nothing more. Jesus spent much of His time explaining that anything a man could do would never be good enough. His was a complete and final sacrifice for our salvation. We don’t even make that decision on our own without His first calling us. Just as He did with Abraham.
Even my faith in the vicarious atonement accomplished by Jesus, if its efficacy depends on the resolve of my will, is not reliable. I can only resort to confidence in the faith instilled in me by the grace of God, as revealed in Ephesians 2:8-9 (and other like passages).