Rambam, Mishneh Torah, Laws of Torah Study 1:2

Just as it is a person’s duty to teach their child, so it is their duty to teach their grandchild, as it is written: “Make them known to your children and your children’s children” (Deuteronomy 4:9). This obligation does not refer only to one’s child and grandchild, but it is a duty resting upon every Jewish scholar to teach all those who seek to be their students, even though they are not that scholar’s own children, for it is written: “You shall teach them diligently to your children” (Deuteronomy 6:7). On traditional authority, the term “your children” in this verse has been interpreted to mean that your pupils are likewise called children, for it is written: “And the sons of the prophets came out” (II Kings 2:3). [CAJE translation. Edited for gender neutrality]