King(s) and Son(s) - Explanation

Apostle John has revealed that God of Heaven as three person (Father, Word and Holy Spirit) - because there are three who are testifying in Heaven: the Father, the Word, and the Holy Spirit, and these three are one -  1 John 5:7

And as a single person, Son Jesus Christ is representing all three of them (Holy Spirit, Father, and the Son) - and there are three who are testifying in the earth: the Spirit(Holy Spirit), and the water(Father), and the blood(Son) and the three are into the one(Jesus Christ) - 1 John 5:8

Even at the situation of paying Tax, Jesus Christ mentioned the Trinity of Heavenly Father as King(s), and the Trinity of Jesus Christ as Son(s) - When they came to Capernaum, the collectors of the two-drachma tax went up to Peter and said, Does your teacher not pay the tax?  He said, Yes. And when he came into the house, Jesus spoke to him first, saying, What do you think, Simon? From whom do Kings of the earth take toll or tax? From their Sons or from others? And when he said, From others, Jesus said to him, Then the sons are free. However, not to give offense to them, go to the sea and cast a hook and take the first fish that comes up, and when you open its mouth you will find a shekel. Take that and give it to them for me and for yourself - Matthew 17:24-27