Tractate Keritot - Chapter 6 - Mishnah 9 כריתות פרק ו׳ משנה ט׳

Rabbi Shimon says: lambs are mentioned before goats in all places. You might think that it is because they are choicer, therefore Scripture states, “And if he brings a lamb as his offering,” (Leviticus 4:32) to teach that both are equal. Turtle-doves are mentioned before young pigeons in all places. You might think that it is because they are choicer, therefore Scripture states, “A young pigeon or a turtle-dove for a hatat,” (Leviticus 12:6) to teach that both are equal. The father comes before the mother in all places. You might think that it is because the honor due a father is greater than the honor due a mother, therefore Scripture states, “A man shall fear his mother and his father,” (Leviticus 19: to teach that both are equal. But the sages have said: the father comes before the mother in all places, because both a son and his mother are obligated to honor the father. And so it is also with the study of Torah; if the son has been worthy [to sit] before the teacher, the teacher comes before the father in all places, because both a man and his father are obligated to honor the teacher.