Likutei Moharan, Part II 46:1/ליקוטי מוהר"ן·תנינא מ״ו:א׳

1Soul-sacrifice is something each Jew does every hour of every day.

2An example of this is giving one’s money to charity. Money is the soul, for “he gives his soul for it” (Deuteronomy 24:15). In other words, to earn the money he first sacrifices his soul in the struggles and dangers. Yet, afterwards, he takes the money and gives it away for the sake of God. It follows, that he is sacrificing his soul.

3The same is true of prayer. In Midrash HaNe’elam (Zohar I, 124b) we find that [prayer] is the concept of “For Your sake we are slain all day long” (Psalms 44:23)—i.e., soul-sacrifice. It takes great struggle and great battle with the thoughts and distractions, and stratagems to flee and escape them. Concerning this it is stated: “For Your sake we are slain…,” as brought in the Midrash HaNe’elam. It follows, that this and similar things are soul-sacrifice.