Why did Israel fail to recognize Jesus even though the Old Testament revealed Him?
Israel failed to recognize Jesus because, although the Old Testament fully revealed Him and they could have known by studying it, they did not know Him. They did not want to know, would not listen, and would not learn, refusing to know any better. That was Israel's plot, even as Gentiles later would come to the light.
Les explains that the Old Testament was full of it, and Israel could have known who He was if they had just studied the book, but Israel did not know. He compares this to America, where people could know the plan of salvation and should know we are in the last days, but they do not. The reason given is that they do not want to; they will not listen, they will not learn, because they do not want to know any better. Les says that was Israel's plot as well. The passage then speaks of the Gentiles coming to thy light, and kings to the brightness of thy right hand, echoing Isaiah 2:2, where the Gentiles shall flow unto it. Les adds, if only Israel could have believed it.