"Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity." Matthew 7:21-23
The deadly pitfall of these people in Matthew 7:21-23 was that they believed another gospel by NOT doing the will of the Father. Another gospel that mixed in self righteousness!(ie:Lordship salvation, good works, etc) These people failed to understand Galatians 2:16; 2:21; 3:1-3, Ephesians 2:8-9, Romans 11:6, Titus 3:5, etc....An example that faith cannot be mixed with works for salvation:
"For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast." Ephesians 2:8-9
"And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then it is no more grace: otherwise work is no more work." Romans 11:6
Doing the "will of the Father" cannot be mixed with self righteousness. "And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day." John 6:40.
If you trust in Jesus and partly in yourself, you came to the wrong Jesus and were deceived....People either trust Him 100% or will perish in the lake of fire...