It might seem that this must be three different creatures, for what creature loses a leg in such a short space of time, and then gains one just as quickly? There is no such creature on earth.
Yet there is an easy solution when we understand the nature of riddles. The answer to the riddle of the sphinx is, “a man.” As a baby, he “walks” on all fours. When he becomes an adult, he walks on two legs, and in his old age, he uses a cane as his third leg.
Now, we could argue that a baby is not really a “man” at all, and when crawling he does not “walk.” This would be true, but it destroys the spirit of a riddle, which allows for figures of speech to be used to conceal the solution, which becomes obvious once it is known.
Similar riddles are presented to us by the prophets of YHWH. For example, in a vision given to the king of Babylon, he sees a great image representing four empires that are to rule the earth; and then a stone cut out not by hands strikes the image, becomes a large mountain and fills the whole earth.1
How the stone becomes a mountain is not explained to him. Nevertheless, the one is directly related to the other, just as a baby becomes an adult.
The prophet Isaiah presents another riddle when he says, “A twig will come forth out of the stem of Jesse, and a sprout from his roots will bear fruit. And the spirit of YHWH will rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and a fear of YHWH.” 2
Your teachers say this is likely a description of the anointed one, and here he is described as a “twig” and a “sprout” which are both small by nature. Yet the same prophecy says: “And in that day there will be the root of Jesse who will stand as a banner for the people. To him the Gentiles will inquire; and his resting place will be glory.” 3
Again, how this happens is not explained, but there must be a process of growth and development, for the “twig” to become a banner for the people and for Gentiles to pay attention, and for his “resting place” to be glory.