The Grace of God Can Be Resisted or Refused

The Church has underscored just as incessantly that the grace of God can be resisted or refused. The real possibility of refusal of grace was affirmed doctrinally by the Council of Trent multiple times in the condemnations of Jensynism. Minitomists hold to the notion that grace is given by God in an intrinsically effective manner, meaning that whatever grace God wishes to us to receive will be received effectively. How then can anyone ever resist or refuse the workings of grace?