"Torah is one and the same with G-d" And both are incomprehensible.
Torah descended through levels, till this world, and it clothed itself in material matters which includes almost all the Torah's commandments and its laws.
Nearly all of the mitzvos involve material objects: Tzitizit are made of wool, tefillin of leather, and so on.
Meaning, that G-d's Will and wisdom, which is basically His essence, are clothed in His Torah and Mitzvos.
So although G-d and His wisdom are beyond man's reach, they are now made accessible to us because they are enclothed in physical objects.
So we may think that when we are doing a Mitzva we are only connected to the lowly material level of G-d and not G-d's essence. Yet it is not so. It is like one who embraces a king. There is no difference in the degree of his closeness and attachment to the king whether he embraces him when the king is wearing one robe or many robes, since the king's body is in them.
The reward in the world to come consists of the soul enjoying the radiance of the Divine Presence, the pleasure in comprehending G-dliness. But it is ONLY a glimmer, a ray of the Divine light. In this world though, through our performing Torah and Mitzvos, we are united with G-d Himself.