Father needed to justify His love to counter His irrevocable death sentence
Father justifies His decision to save mankind and not the fallen Angels because He loves His image by gambling the Highest in heaven at the mercy of Satan, to die and to be risen if He is willing and victorious over disobedience (sin).
Father manifested His love by offering the Highest in Heaven as the Lamb to test His viability of His creation
If Jesus can make it on earth without sinning, any man can because Father knows the mechanics of man whom They made like Them. He traded His irrevocable death for eternal life by killing God, the older Brother of man, for man.
Yehoshua Messiah YAHWEH carved our place in heaven among the highest
Besides Yehoshua (Jesus) Messiah (Christ) YAHWEH (the LORD), Father will host more sons in Heaven in heaven, those of us who overcame Satan to live holy on earth like Gods, representing God on earth.
The righteousness (justification) of Jesus allows Father and He to live in us
Jesus promises that both He and Father will live in us as their temple, if we are holy by keeping all His commandments.
There is a lot of incentive for us to believe in Jesus because unimaginable rewards and responsibilities are awaiting us in eternal life, like authority over nations!