These were not traits which I could imagine in Strickland. Love is absorbing; it takes the lover out of himself; the most clear-sighted, though he may know, cannot realise that his love will cease; it gives body to what he knows is illusion, and, knowing it is nothing else, he loves it better than reality. It makes a man a little more than himself, and at the same time a little less. He ceases to be himself. He is no longer an individual, but a thing, an instrument to some purpose foreign to his ego. Love is never quite devoid of sentimentality, and Strickland was the least inclined to that infirmity of any man I have known. I could not believe that he would ever suffer that possession of himself which love is; he could never endure a foreign yoke. I believed him capable of uprooting from his heart, though it might be with agony, so that he was left battered and ensanguined, anything that(1) came between himself and that(2) uncomprehended craving that(3) urged him constantly to he knew not what. If I have succeeded at all in giving the complicated impression that Strickland made on me, it will not seem outrageous to say that I felt he was at once too great and too small for love.

上面节选中，这句it gives body to what he knows is illusion 怎么理解和分析句式？ I could not believe that he would ever suffer that possession of himself which love is - 句尾的which love is 没看懂上面句式？

anything that(1) came between himself and that(2) uncomprehended craving that(3) urged him constantly to he knew not what. 中that(1)和that(2) 是定语从句，那么that(3)又是什么呢？