A teaching of Yehuda Leib Alter of Ger, from Sfas Emes, Parshat Tzav.
A continuous fire shall burn on the altar; it shall not go out. Leviticus 6:6
It is written in Proverbs, “Love covers all sins,” and in the Song of Songs, “Many waters cannot douse love” (1). Now there is in the heart of every Jew a hidden point aflame with love for God that cannot be put out, and even though “it may not go out” is first a commandment, it is also a promise. As our sages wrote, “Even though fire descends from heaven, it is a mitzvah to bring fire from a human source” (2), and it is likewise in the soul of a person, who needs to renew each day the fiery longing in his heart to serve God. Thus it is written, “The priest must burn wood upon it each morning, each morning,” and every servant of God is called a priest (3). And this awakening of love for God in the hearts of the Jews is the service of the heart, which is prayer, in place of the sacrifices (4).
When your heart burns in this way, every strange thought that arises on your heart (5) will be burned up, as written in the Holy Zohar (6). This is actually the very reason why those strange thoughts arise — that they should be nullified on the heart of the servant of God, raised up and purified. This is why it is written, “It burns all night until the morning” (7). “Until morning” seems redundant — if it burns all night, clearly it burns until the morning — but it is there to hint that through this mixing of the dark and strange thoughts in the heart of the person praying will the “morning” eventually be made.
1) 10:12; 8:7 2) Yoma 21b 3) Leviticus 6:5; “You shall be a kingdom of priests,” Exodus 19:6 4) Sifri Eikev 5, Ta’anit 2a 5) “Strange thoughts” shares the same word, zar, with idolatry, which is called avodah zarah, thus they are not so much bizarre thoughts as misdirected, even immoral ones, and of course the language deepens the metaphor of prayer as sacrifice. 6) 3:27a 7) Leviticus 6:2