What power does a thorn have to pierce my foot? I am well aware that there is a painful corn in my own heel.

This couplet is a profound statement on self-awareness and inner strength. The poet suggests that external struggles, like a thorn entering the foot, are insignificant. The real, known challenge lies within oneself—the 'gatta' (lump or knot) in the heel. It implies that while one might be aware of their own flaws or weaknesses, this knowledge gives them a unique form of resilience. It's a declaration that true strength comes from knowing oneself, not from overcoming external odds.