Final answer:
The statement fills in the blanks with 'ruin' and 'restraint,' reflecting the belief that sin is destructive to the soul and without divine restraint, the soul would be entirely miserable.
Step-by-step explanation:
The correct answer to the student's question is "Sin is the ruin and misery of the soul... if God should leave it without restraint, there would need nothing else to make the soul perfectly miserable." This statement highlights the concept from Christian theology that sin leads to the destruction of the soul's well-being and without God's guiding hand or restraint, a soul would be wholly miserable.
Many theological perspectives believe that sin creates a barrier between humans and the divine, and only through divine intervention can this barrier be lifted, enabling the soul to find true happiness and virtue. The ability for a soul to do good and reject sin is often thought to be possible only with divine help, as the condition of sinfulness is innately opposed to God's law.