One statement was "If God has a plan, why pray, as praying won't change anything."
What if it is God's plan for you to pray. You can't disprove God because the assumption you must make is that God is omnipotent and therefore you can't disprove it because it will just be part of "God's plan".
FOR HARDCORE CHRISTIANS:
If God knew you before you were born, why does he plan certain people to go to Hell?
I asked that a long time ago and got this answer:
"God's plan includes all the possible continencies, including praying - or not praying. For His own reasons, God has told us to pray and promised answers to our prayers.
Someone here likened God to a master chess player, who takes into consideration all the possible moves of the board -- actions, as well as prayers, of the billions of people of the world (past, present, and future) and arranges things according to His will and plan.
His ACTIVE will, and thus His preferred plan, is that every human being ever born would trust Him, be saved, and spend eternity with Him. But, He chose to give man free will so that whether or not they DO spend eternity with Him is contingent on their OWN choice. He does everything short of coercion to convince every human being to turn to Him, but the final decision is THEIRS.
Although He KNOWS that some will choose damnation rather than trust in Him, He does not ACTIVELY plan their damnation. He ALLOWS their damnation because it is what THEY choose for themselves."