עקב ג'. דין ואידך הגדיל עלי עקב. והוא יגוד עקב. זהו שדרז"ל על נחש חבל על שמש גדול שאבד מן העולם זהו גם איש שלומי וגו' הגדיל עלי עקב ועוד אמרו גבי ברכת השבטים אע"פ שדימה יהודה לאריה ונפתלי לאילה חזר וברכם כולם בברכה אחת דכתיב איש אשר כברכתו ברך אותם לומר שהשוום לגבורת ארי ולקלות אילה וזהו והוא יגד עקב אע"פ שדימה דן לנחש כלל גם גד באותה ברכה: "עקב" (heel) - both this interpretation and the other one [that עקב means "because"] are valid. [The phrase] "He will bruise your head" emphasizes [God's] punishment [of the serpent], and "you will bruise his heel" refers to the serpent's treachery. This is why our sages said [in reference to the verse in Job 18:10]: "The snare is laid for him in the ground, and a trap for him in the way." This refers both to the serpent, who was cursed to crawl on the ground, and to the Evil Inclination, who seeks to ensnare man in his ways. Similarly, when Jacob blesses his sons, he compares Judah to a lion and Naphtali to a deer, but then blesses them all together with one blessing, stating that each one should be like his respective animal in strength and agility. This is why it says, "And he shall bruise your head" - even though the likeness of Dan is to a serpent, he too is included in the same blessing.