God didn't even answer his own prayer (if Jesus is God) or the prayer of his perfect son (if Jesus is just God's son) with whom he has a special relationship.
Shortly before his death, Jesus prayed:
John 17:20-21:
“My prayer is not for them alone. I pray also for those who will believe in me through their message, that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me."
Yet there are approximately 47,000 Christian denominations with different beliefs as of 2017 according to the Center for the study of Global Christianity (http://www.gordonconwell.edu/ockenga/research/documents/StatusofGlobalChristianity2017.pdf).
If Jesus' prayer has not been answered then why should anyone believe Jesus' promises about prayer when he said:
"Ask, and it shall be given you; seek, and you shall find; knock, and it shall be opened unto you. For every one who asks, receives; and he who seeks, finds; and to him who knocks, it shall be opened........"(Luke 11).
Or, "Whatsoever you shall ask in my name, that will I do, that the father may be glorified in the son. If you shall ask anything in my name, I will do it (John 14)"?