The Torah writes, "If you will walk in my statutes (chukotai) ..." (Leviticus 26:3). Rabbi Schneur Zalman of Liadi explains that the word chok (statute) is derived from the root chakikah, engraving, hewing or carving: one's study of Torah should be as letters that are hewn out of stone, not as letters of ink that are written on paper.
What does this mean?
The letters and words of ink, through the process of writing, become inseparably connected and united with the paper or parchment. This symbolizes the basic level of Torah learning, in which the student does not give mere lip-service to the Torah's teachings, but becomes joined and united with Torah; his actions reflect his learning.
On a deeper level, though, it is evident that the word written in ink is an entity distinct from that of the paper—although bound together with it. But the letter engraved in stone has no separate existence from the stone whatsoever. The stone itself bends inwards here, protrudes outwards there ... and a letter is formed; the letter is the stone and the stone is the letter.
The carved letter simply does not exist as a distinct entity independent of the stone. In the same way, one's study of Torah should ultimately reach the level of "the engraved letter," where the "self" of the student ceases to exist; his being, his essence, becomes simply Torah.
Such a level of self-effacement was achieved by Moses. He became one with G-d; his "self" ceased to exist. When transmitting G‑d's words of blessing to Israel he used the first person, declaring, "... I will give grass in your fields," for G‑d's Presence (the Shechinah) was speaking through Moses' throat.