Isaac was evidently considering going to Egypt to escape the famine. He was in Gerar when God spoke to him. This was God"s first revelation to Isaac (cf. Genesis 25:23). Therefore, it appears that Isaac may have previously moved north from Beer-lahai-roi. Of course, constant relocating was common for the nomadic patriarchs, and these places were not far from one another. [source][source][source]
The major migration of the Philistines into Canaan took place in the twelveth century B.C. However, there were some Philistines already in Canaan at this time, as is clear from this reference and others in Genesis (cf. Genesis 21:32; Genesis 21:34). [source][source][source][source]
God"s will for Isaac to remain in the land was definite, and He communicated it clearly to the patriarch. Perhaps God wanted Isaac to stay in the land so he would learn that God would "be with you and bless you" ( Genesis 26:3). God reiterated His promise to Abraham to give Isaac a promise to believe and encouragement to obey Him. Promises of protection are also prominent in the Jacob story (cf. Genesis 26:24; Genesis 28:15; Genesis 28:20; Genesis 31:3; Genesis 31:5; Genesis 31:42; Genesis 32:10). [source][source][source]
The promise, however, was that God would protect and bless Isaac, multiply his descendants, and give them "all these lands" ( Genesis 26:4; i.e, the lands held by the various Canaanite tribes). One reason for God"s blessing of Isaac was Abraham"s obedience to God ( Genesis 26:5; cf. Genesis 22:18). Isaac became the spiritual beneficiary of a godly parent, but he had the opportunity to increase God"s blessing on him through his own obedience to God. [source][source][source]
"The Abrahamic blessing will pass to Isaac. Everything included in that blessing will now belong to the Song of Solomon , and in turn will be passed on to his sons. But there is a contingency involved: if they are to enjoy the full blessings, they will have to obey the word of the LORD. And so obedience is enjoined here, with the example of how well Abraham obeyed." [1][source]Genesis 26:5 sounds like Abraham kept the commands, statutes, and laws of the Mosaic Covenant before they were in existence. It seems to contradict Genesis 15:6 that says God justified Abraham because of his faith. [source][source][source]
"Ultimately, we should attempt to find the meaning of this verse in the larger strategy and purpose of the Pentateuch. Did the author of the Pentateuch intend to depict Abraham as a model of faith or as a model of obedience to the law? Curiously enough, the overwhelming majority of biblical scholars have read this passage as if the verse intended to show Abraham"s life as an example of obedience to the law (Gesetzesgehorsam). [source][source][source]
"It appears reasonable to conclude ... that the importance of Genesis 26:5 lies in what it tells us about the meaning of the deuteronomic terms it uses. It is as if the author of the Pentateuch has seized on the Abrahamic narratives as a way to explain his concept of "keeping the law." The author uses the life of Abraham, not Moses, to illustrate that one can fulfill the righteous requirement of the law. In choosing Abraham and not Moses, the author shows that "keeping the law" means "believing in God," just as Abraham believed God and was counted righteous ( Genesis 15:6). In effect the author of the Pentateuch says, "Be like Abraham. Live a life of faith and it can be said that you are keeping the law."" [2][source]
"Israel would immediately see Torah (Law) terminology in the record of Abraham, and would be prompted to keep the Law." [3][source]