I think it is interesting that Jesus had told them clearly who He was/is, but because of their own disbelief they did not believe Him. They actually blamed Jesus for their doubt. Their doubt was because they placed their faith in a religious system and not in God Himself, but they blamed Jesus as if He had caused them to deny what they had seen and heard themselves.
It's not that different today. People will say "if God is real then show me some miracle." All the while they are denying all the miracles that have already taken place and continue to take place every day. Jesus said, "My sheep hear My voice," and herein lies the deepest truth about Jesus. All are called, but few accept the free gift of salvation. Those whom are called and accept the free gift of salvation are the Sheep of His pasture. Those who are called and reject the call are not His sheep, thus those who want Jesus to tell them clearly, over and over and over again who He is.
Jesus has already said and done all that is necessary for all mankind to come to Him and believe, and even more than that, keeps on coming to them and calling them and showing them and unveiling Himself, and they continue to deny Him.
- They continue to say 'show us clearly' and blaming God for their doubt. All the while they believe in other gods and other things that neither live or have ever shown themselves clearly.
- They believe in those who have never called them or spoke to them, those who make no spiritual effort to bring them unto themselves.
- They believe in other gods who have never breathed or walked or lived.
- They believe in gods that cannot speak or teach or show love or mercy or forgiveness. They believe in all kinds of silly formulas and systems and rituals and cultural activities that neither are from God nor bring you closer to God. They deny the Son of God, that lives and is full of mercy and forgiveness and call on other gods that have done nothing for them, ever.
- They believe in a fantasy made up by religious and intolerant men, ignorant of the truth about God, but full of themselves.
- They believe this way, not because they found their truth for themselves, but because someone else forced them to receive it.
- They don't come to Jesus because their leaders will make their lives and the lives of their families a living hell. It was that way when Jesus walked the earth and it is still that way among a great many.