2. Belief and disobedience are the same thing. We get punished for disbelief just as for disobedience.
Take care, brethren, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God. But exhort one another every day, as long as it is called “today,” that none of you may be hardened by the deceitfulness of sin. For we share in Christ, if only we hold our first confidence firm to the end, while it is said, “Today, when you hear his voice, do not harden your hearts as in the rebellion.” And to whom did he swear that they should never enter his rest, but to those who were disobedient? … So we see that they were unable to enter because of unbelief.
Hebrews 3:12-15, 19 (RSV) (italics added).
Therefore, while the promise of entering his rest remains, let us fear lest any of you be judged to have failed to reach it. For good news came to us just as to them; but the message which they heard did not benefit them, because it did not meet with faith in the hearers. For we who have believed enter that rest, as he has said, “As I swore in my wrath, ‘They shall never enter my rest,’” although his works were finished from the foundation of the world. For he has somewhere spoken of the seventh day in this way, “And God rested on the seventh day from all his works.” And again in this place he said, “They shall never enter my rest.” Since therefore it remains for some to enter it, and those who formerly received the good news failed to enter because of disobedience,… Let us therefore strive to enter that rest, that no one fall by the same sort of disobedience.”
Hebrews 4:4-6, 11 (RSV) (italics added).
But we are not of those who shrink back and are destroyed, but of those who have faith and keep their souls.
Hebrews 10:39 (RSV).
This comports with the Catholic understanding that faith is an act of the will. Therefore like any sin disbelief, or doubt, is a decision you make. If it were not, why would the scriptures place us under the threat of punishment for it?