Negative commandment · Lo Ta’aseh #306 of 613
Not to take a mother bird together with the young
שלא ליקח אם על הבנים
The verse · Devarim 22:6
כִּי יִקָּרֵא קַן־צִפּוֹר לְפָנֶיךָ בַּדֶּרֶךְ בְּכׇל־עֵץ אוֹ עַל־הָאָרֶץ אֶפְרֹחִים אוֹ בֵיצִים וְהָאֵם רֹבֶצֶת עַל־הָאֶפְרֹחִים אוֹ עַל־הַבֵּיצִים לֹא־תִקַּח הָאֵם עַל־הַבָּנִים
“If a bird’s nest chance to be before thee in the way in any tree, or on the ground, whether they be young ones, or eggs, and the mother bird sitting upon the young, or upon the eggs, thou shalt not take the mother bird together with the young:”
The Rambam’s words
Not to take a mother bird together with the young, as [Deuteronomy 22:6] states: "Do not take the mother bird together with the young."
שלא ליקח אם על הבנים, שנאמר "לא תיקח האם, על הבנים" (דברים כב,ו).
Why · Sefer HaChinuch #544
To not take the mother upon the young
“It is from the roots of this commandment [that it is] to put into our hearts that the providence of G-d, may He be blessed, is upon all of His creatures — with the human species individually, as it is written (Job 34:21), “For His eyes are upon a man’s ways, etc.”; and upon the other species of animals generally, meaning to say that His desire, may He be blessed, is towards the existence of the [particular] species.”
Where in the Mishneh Torah
Hilchot Ritual Slaughter הלכות שחיטה