I have told you through the works I do in my Father’s name that I am the Christ and you still do not believe me. Jesus had kept the community in suspense long enough, and they couldn’t wait any longer. He had to let them know - in plain words - if he was the one for whom they had been waiting. There couldn’t be any margin for error. Doing so was too risky. It was true, as Jesus was saying, that they had seen the works that he was doing, and there was some probability of Jesus being the Christ of God, but that was still not enough. They needed him to be direct and plain. But Jesus stood his ground and in essence told them: “find out for yourselves! Those who have seen my works have already made up their minds and have decided on where they stand.” Why would the people not believe in Jesus even after seeing his works?
As is often said, familiarity breeds contempt. The majority of those who were privileged enough to witness Jesus at work knew him at a personal level. They knew his family, and they knew his background. They had seen him grow up in their midst. He was one other own. Consequently, to them, he could not be the anointed one of God, for according to what they had learnt, when the Christ comes, no one would know from whence he comes (cf. John 7:27). To them, the Christ had to be a mysterious figure; the Christ had to be of a different “species” and “speak” a different language, so to speak. In other words, the Christ had to rouse within the people a feeling of awe and fear. To them, the Incarnation was an oxymoron: the Christ could in no way live among them as one of them. And so they continued to wait for he who had already come and was already in their midst. 
Sometimes we tend to be like the Jews who wanted Jesus to reveal the self to them despite seeing his works. Like those Jews, we at times find ourselves asking for more proof from Jesus. Like them, we too might have seen the works of Jesus but are still expecting more. The challenge that Jesus threw to the Jews is the same that he is throwing at us: we have to stop looking for what is not there and instead focus upon that which is in front of our eyes. Jesus has come and has reconciled us to the Father. Because of Jesus, we can once again call God our Father. There can be no greater proof (that he is the Christ) than this. There can be no greater sign than a people who had been estranged from God getting re-united with God.