It is the power to reject Him. It is the power to determine the quality of our lives here and now and our fates their and then. It is the power to live or to die. We must receive God's grace by faith. It is more than believing , for even Satan and his demons believe.
Faith is more than religious observance.
A lot of religious people will go to hell. You may take your place in your pew every Sunday. But just because the cat had her kittens in the oven doesn't make them biscuits. It is more than benevolent do-goodism. A lot of very good people will go to Hell.