What does Genesis 26:28 mean?
In response to a surprise visit from King Abimelech, Isaac reacts with defensiveness and suspicion. After all, the king had sent Isaac away due to his growing wealth and power (Genesis 26:12–16). Isaac concluded that the king hated him. This probably also stems from the king's anger at catching Isaac in a dangerous lie (Genesis 26:6–11). The people of the region, despite Isaac's willingness to move, had also given him much grief over wells in the Valley of Gerar (Genesis 26:18–22).Now the king reveals he has come to Isaac to make peace, not war. He wants to make a treaty with Isaac, much as a prior king, also named Abimelech, had made a treaty with Abraham at Beersheba. Why this sworn pact or covenant? The king says they have seen plainly that the Lord has been with Isaac. The king understands that Isaac's God is powerful and that He has used that power to bless Isaac. Abimelech believed in God and hoped to benefit by being allied with God's man Isaac.
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.
Genesis 26 focuses on God's assurances to Isaac to be with him and to bless him, mostly while Isaac and his household are settled in the land of the Philistines. Just as Abraham did, Isaac fearfully lies about his wife being his sister, nearly bringing disaster on Abimelech and his kingdom. Still, God blesses Isaac with greater and greater abundance to the point that Abimelech sends Isaac away because he has become too powerful. After continued disputes over water rights, Abimelech and Isaac eventually make a covenant of peace.