Answer:

The soul of Moshiach is one of the first things in existence and one of the loftiest. Its creation preceded all other aspects of creation. As our sages say, on the second verse of Bereishit, “And the earth was null and void, and a spirit of G-d hovered over the face of the water,” “The spirit of G-d: this is the soul of Moshiach.”

As long as the hour of Redemption has not yet come, this soul cannot be revealed within Moshiach. Only with the complete Redemption, when all of creation will be elevated, the “spirit of G-d” will be revealed in it. This, simply, is the meaning of the Midrash on the verse in Psalms: “I have borne you today.” When the time will come, G-d will say, “It is upon me to create a new creation. Only then, will a new soul be implanted in Moshiach and he will be created anew.

In the book “Sfas Emes” by Rabbi Yehuda Aryeh of Gur of blessed memory, it is explained that as long as Moses was in Egypt, even as he was working to bring about the redemption from Egypt, he was “concealed.” In other words, his full soul powers were not revealed. Only after he redeemed the Jews in actuality and took them out of Egypt was he revealed, and all the powers of his soul were lit up. The same is true of Moshiach. As long as he is in exile, even as he works to redeem the people, he is concealed. The full range of his soul powers are not evident. When Moshiach comes, he will be fully revealed with all his powers.

Even more so: It is possible that even with the complete redemption, Moshiach’s soul powers will not all be revealed immediately. This we are given to understand from Maimonides, who writes that Moshiach will not necessarily do miracles. It is true that after the Redemption various miracles, such as the resurrection of the dead, will take place, but these are not required to identify him as Moshiach. Only later will his miraculous powers take root in him and will be revealed.

(Bereishis Rabba, 2:4. Tehillim 2:7. Sfas Emes, Rosh Hashana, 11:2)