Even "dead" faith (faith without works) can save.
16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified. (Galatians 2:16)
Works justify no man before God.
1 What shall we say then that Abraham our father, as pertaining to the flesh, hath found? 2 For if Abraham were justified by works, he hath whereof to glory; but not before God. 3 For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness. 4 Now to him that worketh is the reward not reckoned of grace, but of debt. 5 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness. (Romans 4:1-5)
These scriptures assert the truth that it is faith that saves, not works.
8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: 9 Not of works, lest any man should boast. (Ephesians 2:8,9)Salvation is a gift. Gifts do no require any meritorious work to receive or to keep. If salvation does require work, then it wasn't a gift, but rather a debt owed to the worker.
Those who are trusting in their works in any capacity to save them have made God out to be a liar.
9 If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son. 10 He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son. 11 And this is the record, that God hath given to us eternal life, and this life is in his Son. 12 He that hath the Son hath life; and he that hath not the Son of God hath not life. (1 John 5:9-12)
The believer receives the gift of eternal life, not temporary life that can vanish if a displeased master decides to become an Indian giver and take back the gift.
When a son of God is birthed by God (which is not by blood, nor by the will of the flesh, nor the will of men -- John 1:12,13) he becomes known to God and will forever be his child. He might not walk after the spirit and instead indulge the flesh (i.e. be the black sheep of the family), but he remains a son, sealed with the holy Spirit of promise:
As Paul says to the Ephesians in chapter 1:
13 In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, 14 Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.
This is the father's will ,b>as it pertains to salvation:
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst. 36 But I said unto you, That ye also have seen me, and believe not. 37 All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out. 38 For I came down from heaven, not to do mine own will, but the will of him that sent me. 39 And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day. 40 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 6:35-40)
Recap:
God is repeating himself so that even the thickest head can understand, if he wants to.