This is the idea of the second paragraph of the Shema, which corresponds to fear of Hashem, as it is written in that passage (Devarim 11:16): “guard yourself, in case your heart becomes tempted to rebel against Hashem...”
The second paragraph of the Shema is when we accept the principle of reward and punishment for our actions, and we commit to guard ourselves against sin. This ability to guard ourselves from sin comes from fear and awe of Hashem as our King.
This is the meaning of what is written (Bereishis 29:33): “For Hashem has heard that I was disliked,”
The simple meaning, as explained earlier in the maamar, is that Leah was thanking Hashem for giving her a son, because now her husband will love her more. In the literal meaning, “כִּּי ש ָּמַע ה'” means “for Hashem has heard,” and “כִּּי ש ְנוּאָּה אָּנ כִּי” means “that I was disliked.”
The Alter Rebbe is interpreting the phrase “כִּּי ש ָּמַע ה'” to mean “for Hashem has caused me to hear,” and “כִּּי ש ְנוּאָּה אָּנ כִּי” to mean “because I despise myself.” I.e., because I humble myself towards Hashem, Hashem causes me to “hear” Him and come to truly fear Him, as the Alter Rebbe will continue to explain.
