For many people, they ask, “If God is sovereign like the Calvinists says, then why should I pray?” I think this is the wrong question. First of all, the Bible does not use this doctrine to discuss abstract philosophical issues of time and space—rather, it intends to emphasize His grace and power in salvation.
Second, I would suggest a better question, which is actually the opposite question I had when I first believed the ‘doctrines of grace’ (another historical phrase meaning “Calvinism”). I asked myself, “If God cannot sovereignly change hearts and minds, then why do I pray?” This is the opposite question. For example, why to I pray for friends and family to accept Christ if God can’t answer that prayer?
Yet Paul prayed like this:
"Brothers, my heart's desire and prayer to God for them is that they may be saved," (Rom 10:1).
"Finally, brothers, pray for us, that the word of the Lord may speed ahead and be honored, as happened among you," (2 Thess. 3:1).
Apparently, God can decisively overcome human resistance and save them. He is not like Satan, merely have “persuasive power”. He can answer these prayers. It you don’t believe God can actually cause people to believe and be saved, then why are you praying?
If you believe in prayer, you must inevitably accept God’s sovereignty in election.