If we say that we have not sinned, we make Him a liar, and His word is not in us. (I John 1:10 NKJV)
If a person thinks God should save them because of how good and moral they are, then they in effect are saying they have not sinned.
Sin defined is missing the mark and the mark is being holy as God is holy. There is not a man alive or who has ever lived except Christ who has not missed the mark. We have all sinned and to say we have not is to tell God Almighty that He is a liar.
This is a litmus test. If a person thinks they can get into God's good graces because they have been good enough themselves whether by living a good moral life or doing religious ritual or both, then they are saying they have not missed the mark, in effect saying they have not sinned...His word is not in that person. They are not a true Christian.