Faith in Christ is not the cause of the new birth. Faith is the result of the new birth. We believe according to the working of God's mighty power, by the operation of His grace. The new birth is something done to you, for you and in you by God's sovereign, irresistible grace. It is not something you do.
Martin Luther correctly asserted, "If any man ascribes anything to his or her salvation, even the very least thing, or the free will of man, he knows nothing of grace, and he has not learned Jesus Christ rightly."
Here is a powerful word "Born." Salvation is the gift of life, eternal life. When our Lord declares, "Ye must be born again," he is saying you must be the object and recipient of Divine power. Just as God created the world, God must create life in your soul. He must breathe into you the breath of life by His Spirit or you will perish in your sins. We are all spiritually dead, helplessly lost by nature. Our only hope is that God the Holy Spirit will give us life.
Here is a profound word "Again." The new birth is a mystery of grace. It cannot be explained; neither can it be fully understood. It's a work of God beyond our comprehension. When our Lord says, "Ye must be born again," the word again has two meanings. First it means you must be born a second time. Second it means you must be born from above.
James tells us that every good and perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning. He then tells us what he is teaching in the next verse. Of His own will begat he us with the word of truth (James 1:17-19). By our first birth we were born in sin and the lust of the flesh. By our second birth, we became wise unto salvation and are made children of promise like Isaac, Abraham's son.
Make sure, make very sure that you are born again and a child of promise. The path of the just is as a shining light, that shineth more and more unto a perfect day (Proverbs 4:18).