Is it at all possible to achieve this unity called Devekut?
The answer is that it is not achieved through human effort, but by virtue of Divine revelation – as when God gives the Torah or the mitzvah.
And the efficacy of Torah does not depend on the degree of penetration into its content or meaning, or even on the purification of one's mind and actions in relation to the ethical ramifications of doing good or combatting evil.
Even the social benefits, no matter how great, are incidental and peripheral.
The essential fact about the Torah is the way it comes to man, across the abyss of the infinite, as a communication of God's will, God's thought.
And the more external reasons and justifications a person gives for living according to Torah, the more scaffolding and superstructure he adds to the essential revelation.
True, there are many people who need these reasons, for a while or for all their lives.
One circumcises his son because it is hygienic or traditional, and one eats kosher because it is healthy, and so forth.
No matter how subtle and sublime the rationalizations, it does not change the fact that, ultimately, one is not doing the mitzvah because it is good or pleasant or beneficial but because God has said, "I want it."
–Rabbi Adin Steinsaltz
From “Problems of Receiving the Shechinah” in The Long Shorter Way by Rabbi Adin Steinsaltz