I love the man that can smile in trouble, that can gather strength from distress, and grow brave by reflection. 'Tis the business of little minds to shrink, but he whose heart is firm, and whose conscience approves his conduct, will pursue his principles unto death.

This quote is saying that a valuable quality to have is not to despair or lose hope in difficult situations. It is easy for someone with a small mind to give up and feel defeated, but a brave and strong person finds strength and courage even in distress, and has the courage to continue, no matter how tough or challenging it may be. Even if it means sacrificing their own life, they will remain true to their moral principles.