Summary
This quote implies that envy acts as a powerful motivating factor. When a person feels envious of someone else's success, possessions, or talents, it serves as a catalyst for self-improvement. Envy sharpens "sight" in the sense that it helps individuals recognize what they desire and strive to acquire it for themselves. It drives ambition and pushes people to surpass their current limitations. However, the quote also implies that this motivation may come at the expense of negative emotions and unhealthy comparisons to others.