Why does the Bible make this such an emphasis?
It has to do with the nature of God. The Triune Godhead: Father, Son, the Holy Spirit.
It is impossible to appreciate the working of the Holy Spirit today without accepting the realities within the Triune Godhead. Jesus the Son was totally dependent on His Father, and would only do what the Father wanted. Whereas the Father lovingly and trustingly sent His Son to Planet Earth with full authority.
This beautiful harmony in the Godhead is the model for human father-son, father-daughter relationships.
It´s rooted in the Ten Commandments:
“Honor your father and your mother, that your days may be long in the land that the LORD your God is giving you” (Exodus 20:12)
Apostle Paul made this a special emphasis:
“Honor your father and mother” (this is the first commandment with a promise)” (Ephesians 6:2)
Jesus even underscored the negative consequences of mocking (=reviling) your father or mother:
“For God commanded, ‘Honor your father and your mother,’ and, ‘Whoever reviles father or mother must surely die.’” (Matthew 15:4)
It is noteworthy that the two last verses of the Old Testament make the father-child relationship a special point, pointing to the sending to earth of Jesus the Son – by God the Father:
“Behold, I will send you Elijah the prophet before the great and awesome day of the LORD comes. And he will turn the hearts of fathers to their children and the hearts of children to their fathers, lest I come and strike the land with a decree of utter destruction” (Malachi 4:5-6)