The prior verse indicated that Isaac has been blessed by God, and this verse gives details on the extent of this success. Under God’s great blessing, Isaac’s crops yielded a hundredfold return (Genesis 26:12) even in a time of famine (Genesis 26:1). The result is great and increasing wealth. This is on top of the apparently enormous wealth Isaac had already inherited from Abraham (Genesis 25:5). In short, Isaac was most likely one of the richest men in the region. Like his father, God is making it clear to Isaac that he will be blessed for following God’s instructions (Genesis 22:15–18). The covenant God made with Abraham applies to Isaac, and it applies personally, not merely because Isaac is Abraham’s son (Genesis 26:2–5).
Genesis 26:6–35 describes Isaac’s interactions with the Philistines while living in and around the land of Gerar. After Isaac is caught in a lie about Rebekah being his sister, king Abimelech is angry. However, he protects Isaac and Rebekah. God blesses Isaac abundantly, and his wealth grows to the point where his power provokes the king to send him away. Following a series of disputes over water rights, the king and Isaac eventually make a treaty of peace. God appears to Isaac for a second time, telling him not to fear, and renewing His promises.