Tanya Chapter 40 part 3

The secret of intention?  The  power to send things up from the material world into infinitely higher realities. Man’s animating, speaking soul is subject to the condition which affects the totality of this world –– kelipat nogah. When speaking worthless things, the vivifying soul constitutes a concealing veil, obscuring the Divine life energy within it. However, when the vivifying soul enunciates and powers words of Torah and prayer, it cannot conceal the Divine. In fact, it becomes transformed in the process, being that Torah and mitzvah completely disclose Hashem. However, if the intention to connect to Hashem is lacking, then although there is no concealment, there is a huge constriction which limits the holiness of these words to the realm of the physical. In contrast, when kavanah -– intention –– is infused into  words of holiness, it enlivens them and raises them up to their place, to the ten Sefirot of the higher worlds, allowing their true essence to shine.