When Jesus told the woman to go and "sin no more" and the Apostle Paul told the church " You are responsible for your own salvation", these two instances might put a little crimp into the idea of permanency. And to answer the 3:16 folks, better look real close at 3:5.
And John 3:36.
John 3:36
John the Baptist's primary message: "He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him."
Jesus message of salvation to the Pharisee: "18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God."