What does Genesis 26:4 mean?
In the previous verse, God appeared to Isaac with a powerful message: I am establishing the oath I swore to Abraham with you, as well. I will be with you. I will bless you. The Lord wanted Isaac to understand that all of the promises his father relied on were for him, as well (Genesis 12:1–3).Now the Lord goes further in repeating those promises: Isaac's offspring would be as the stars of heaven. His offspring would possess all the land of Canaan. Through Isaac's offspring, all the nations of the earth would be blessed. We understand that global blessing to come through the life, death, and resurrection of Isaac's descendant Jesus Christ (Matthew 1:1–16; Luke 3:23–28).
Of course, it's only logical that all those things must happen through Isaac for God's promises to Abraham to hold true. But the Lord is intent that Isaac understand these promises are for him, as well. God wants Isaac to take them personally and not to merely see himself as an extension of Abraham. The Lord would be with Isaac.