@giujohn,
In Exodus 3:14 Moses is talking to the Angel of the Lord, who is manifest in a burning bush. That Angel is clearly God Himself, as the context of that entire passage implies. Moses asks 'The Lord', whom shall I tell the Israelites who sent me? To which the angel says "You are to tell them I Am has sent you. That is my name...." the I AM is the 4 letters YHVH, or YHWH, from which we derive the name Jehovah, or Yahwey. In Hebrew it is just 4 consonants, and it is often referred to as the "Tetragrammaton."
In John chapter 8, Jesus is involved in a discussion with some Jewish leaders who have questioned his authority. This, and several preceding and following chapters are replete with "I am" statements by Jesus. "I am the light of the world...," "I am the bread of life...," etc. But most significant are 3 statements by Jesus, which offended the Jewish leaders enough to want to stone him to death (the punishment for blaspheme - which is to equate oneself with God. ) :
1) "You are from below, I am from above; you are of this world, I am not of this world. I said therefore to you, that you shall die in your sins; unless you believe that I AM, you shall die in your sins. (John 8:23-24)
2) "When you lift up the Son of Man, then you will know that I AM, and I do nothing on my own initiative, but I speak these things as the Father taught me." (John 8:28)
3) (this one is most significant) If we take Jesus word here in context with the Angel of the Lord passages in Genesis and Exodus, and elsewhere in the OT, they are very illuminating. First Jesus makes the statement: "Your father Abraham rejoiced to see my day, and he saw it and he was glad." So Jesus is essentially saying that he had an encounter with Abraham; and when we read in Genesis, Chapter 18, Abraham is visited by two angels, one of which is called "The LORD."
So naturally the Jewish leaders challeng Jesus, "You are not yet fifty years old, and have you seen Abraham?" To which Jesus replied: "Truly, truly, I say to you, before Abraham was born, I AM." (John 8:56-58)
So in claiming to be the same I AM that both Moses and Abraham encountered, Jesus was claiming to be God. He claimed eternality and equality with God. This is why in the next verse we read:
"Therefore they picked up stones to throw at him..." In their view he was guilty of blasphemy, equating himself with God. And for that he offered no apology or explanation. In fact he continued to make the same utterance once more:
"They answered him, 'Jesus the Nazarene.' He said to them, I AM. And Judas also who was betraying him, was standing with them. When therefore he said to them, 'I AM,' they drew back, and fell to the ground." (John 18:5-6)
The author of John wants to make it very clear that Jesus is God, by first making it clear that Jesus himself made that claim. But we also have the introdiction to the gospel in Chapter 1, which makes it rather explicit.