And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth. And of his fulness have all we received, and grace for grace. For the law was given by Moses, but grace and truth came by Jesus Christ. - John 1:15-17

The greatest evidence of the new birth is the fact that, not only did some people recognize Jesus, they saw Him for Who He was, the Son of God! Because God loved them with an everlasting love, He drew them in the new birth (Jeremiah 31:3). God chose His children according to His sovereign mercy (Romans 9:15-16) and He sends His spirit into their hearts with the same irresistible power (John 3:7-8).

So, John is basically saying that we got a "free gift" as a free gift. Salvation by grace is not something that we obtain by our will or works or even by a prayer or decision. Any system that requires we do, say, or believe anything is law type system. Saved by grace means that Jesus did it all! Our faith and belief in Christ is the way we can know that we are saved.