If God desires a man to have grace, that man will have grace.
RCs presume they are stronger than the will of God and the actions of the Holy Spirit.
Utter hubris.
Scripture says grace is free and unmerited. Read Ephesians 1 and 2 and learn who is stronger — God or man.
"IF"? Again you are at odds with 99% of those who call themselves Christian. God gifts Grace to everyone sufficient for their Salvation. Irresistible grace is a fabrication of a French lawyer, not the Holy Spirit. It is a perversion of the concept of efficacious grace. I would encourage you to expand your knowledge beyond the musings of Calvin. Read your whole bible. Then, if you are still interested in the concept of Irresistible Grace read Congregatio de Auxiliis.
Peace be with you.