"31 So Jesus said to the Jews who had believed in him, “If you abide in my word, you are truly my disciples, 32 and you will know the truth, and the truth will set you free.” 33 They answered him, “We are offspring of Abraham and have never been enslaved to anyone. How is it that you say, ‘You will become free’?”
34 Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is a slave to sin. 35 The slave does not remain in the house for ever; the son remains for ever. 36 So if the Son sets you free, you will be free indeed.37 I know that you are offspring of Abraham; yet you seek to kill me because my word finds no place in you. 38 I speak of what I have seen with my Father, and you do what you have heard from your father.”
39 They answered him, “Abraham is our father.” Jesus said to them, “If you were Abraham's children, you would be doing the works Abraham did, 40 but now you seek to kill me, a man who has told you the truth that I heard from God. This is not what Abraham did. 41 You are doing the works your father did.” They said to him, “We were not born of sexual immorality. We have one Father—even God.” 42 Jesus said to them, “If God were your Father, you would love me, for I came from God and I am here. I came not of my own accord, but he sent me. 43 Why do you not understand what I say? It is because you cannot bear to hear my word. 44 You are of your father the devil, and your will is to do your father's desires. He was a murderer from the beginning, and has nothing to do with the truth, because there is no truth in him. When he lies, he speaks out of his own character, for he is a liar and the father of lies. 45 But because I tell the truth, you do not believe me. 46 Which one of you convicts me of sin? If I tell the truth, why do you not believe me?47 Whoever is of God hears the words of God. The reason why you do not hear them is that you are not of God.”"
John 8:31-47
The cruciality of our Lord's deity for true faith has been a cardinal point not only in the discussion in this chapter, but throughout John's record, and it is further borne out by a distinction that is made in 30 and 31 between the two Greek expressions for 'believed'. The first implies a faith that involves personal reliance, trust and commitment, while the second, in 31, is merely nominal and superficial, akin to that of the disciples in 2:23, where we are told that Jesus was not prepared to commit Himself to them. Jesus' words to the Jews that believed in this way have therefore the effect of sifting them, and exposing the fatal lack in their attitude to Him. Hence their immediate reaction in 33, objecting to the suggestion that they needed to be made free, and their increasing resistance to His radical probing of their basic attitudes (37, 39). What really hindered them from becoming disciples and relying on Him was their reliance on 'other things', e.g. their traditional welcome for Abraham. This Jesus deals with in 34, 35. Though freeborn, they had become slaves and needed to be set free. But they refused to recognise their need and their plight, and therefore no salvation could be theirs. Only the Son can make men free. And the more He says, the more they reveal their fundamental lack of understanding of the things of God, a blindness due to their unwillingness to receive His testimony concerning Himself (43); until finally belief in Him that refuses to acknowledge His deity is exposed as being of the devil (44). So central is the doctrine of the deity of Christ for true, saving faith.