Likutei Moharan 67:10/ליקוטי מוהר"ן ס״ז:י׳

110. {“Also on the day of the bikurim (first-fruits), when you bring a new-meal offering to God on your Shavuot Festival, it shall be a sanctified mikra (convocation) to you; you shall not do any laborious work” (Numbers 28:26).}

2This is the meaning of “Also on the day of the BiKuRim (first-fruits).” This alludes to bringing forth the soul without the hardships of giving birth—the aspect of “in anguish, k’maBKiRah (like she that gives birth for the first time)” (Jeremiah 4:31), which refers to the hardships of childbirth. It also alludes to raising the soul, the aspect of “as one would grieve over a BeKhoR (firstborn)” (Zechariah 12:10)—namely, the troubles associated with raising children.

3“A sanctified miKRA (convocation)” alludes to glory, which is the aspect of sanctity, as in “it will be sanctified with My glory” (Exodus 29:43). [Tzedakah] KoRAi (calls forth) the feet, as in “yiKRAeihu (that called forth) tzedek wherever he set his foot,” which was explained above.

4[Rebbe Nachman] did not explain the rest.