It All Starts with Kibbud Av V'Em: Honoring parents as the cornerstone of "one person, one heart"

(12) Honor thy father and thy mother, that thy days may be long upon the land which the LORD thy God giveth thee.

(3) Ye shall fear/revere/be in awe every man his mother, and his father, and ye shall keep My sabbaths: I am the LORD your God.

(Mishnah Peah 1:2) These are precepts for which no fixed measure is prescribed: [leaving] the corner [of a field unharvested], [the offering of] the first fruits, the appearance-offering, [performing] deeds of kindness, and the study of Torah. (Shabbat 127a) These are precepts, the fruits of which man enjoys in this world, [while] the principal [reward] is preserved for him in the World-to-Come. They are: honoring father and mother, [performing] deeds of kindness, early attendance in the House of Study morning and evening, providing hospitality to guests, visiting the sick, participating in making a wedding, accompanying the dead [to the grave], concentrating on the meaning of prayers, making peace between fellow men and between husband and wife— and the study of Torah is equal to them all.

Composed: Middle-Age Spain, c.1255 – c.1285 CE, Anonymous; possibly by R. Aharon HaLevi

(2) From the roots of this commandment is that it is fitting for a person to acknowledge and return kindness to people who were good to him, and not to be an ungrateful scoundrel, because that is a bad and repulsive attribute before God and people. And he should take to heart that the father and the mother are the cause of his being in the world; and hence it is truly fitting to honor them in every way and give every benefit he can to them, because they brought him to the world, and worked hard for him when he was little. And once he fixes this idea in his soul, he will move up from it to recognize the good of God, Blessed be He, who is his cause and the cause of all his ancestors until the first man (Adam), and that he took him out into the world's air, and fulfilled his needs every day, and made his body strong and able to stand, and gave him a mind that knows and learns - for without the mind that God granted him, he would be 'like a horse or a mule who does not understand.' And he should think at length about how very fitting it is to be careful in his worship of the Blessed be He.

Rabbi José said: Isaac observed mourning during three years || for his mother. After three years he married Rebecca, and forgot the mourning for his mother. Hence thou mayest learn that until a man marries a wife his love centres in his parents. When he marries a wife his love is bestowed upon his wife, as it is said, "Therefore shall a man leave his father and his mother, and he shall cleave unto his wife" (Gen. 2:24). Does a man then leave his father and mother with reference to the precept, "Honour"? But the love of his soul cleaves unto his wife, as it is said, "And his soul clave (unto Dinah)" (Gen. 34:3); and it says, "And he shall cleave unto his wife" (Gen. 2:24).

(Chayei Adam is a work of Jewish law by Rabbi Avraham Danzig (1748–1820; Translation below by Gerald Blidstein, Honor Thy Father and Mother (Augmented Edition), Brooklyn, NY: Ktav, 2019, p. 57.)

...Obviously, a man ought to love his parents as himself, for they are included in "You shall love your neighbor as yourself (Lev. 19:18). But the love of parents is compared to the love of God, as we read in Zohar: "a man ought to do all for his mother and father and love them more than himself, and his sould and all he possesses ought to be held as nought in his zeal to do their will."

Our sages have said that the obligation of a son toward his father are repayment of the debt owed the parents for their good nurture...Part of this repayment must be that he love them strongly, as they loved him, and that he not consider them an unwelcome burden...

"Honor" is a matter of thought, deed, and speech. In thought,...he must honor them in his heart, that they be in his eyes great and distinguished, though they are unimportant in the eyes of other men. And this is the essence of "honor," for if one does not do so, he fits the description of Scripture: "Forasmuch as this people draw near, and with their mouth and with their lips do honor Me, but have removed their heart from Me..." (Isaiah 29:13).