Bereishit (26:4), “And I will multiply your seed like the stars of the heavens, and I will give your seed all these lands, and all the nations of the earth will bless themselves by your seed. (26:5) Because Abraham hearkened to My voice and kept My charge, My commandments, My statutes, and My instructions.”
Bereishit (26:24), “And HaShem appeared to him on that night and said, I am the God of Abraham your father. Fear not, for I am with you, and I will bless you and multiply your seed for the sake of Abraham My servant. (26:25), And he built an altar there, and he called in the name of HaShem, and he pitched his tent there, and Isaac’s servants dug a well there. (26:26) And Abimelech went to him from Gerar, and a group of his companions and Pichol his general. (26:27) And Isaac said to them, Why have you come to me, since you hated me, and you sent me away from you? (26:28) And they said, We have seen that HaShem was with you; so we said, Let there now be an oath between us, between ourselves and you, and let us form a covenant with you.”
Isaac was twice blessed in the merit of Abraham his father and not by his own merit because he did not yet call out in the name of HaShem (publicize the faith) (as Abraham had done, Bereishit 12:8 & 13:4). Isaac then called out in the name of HaShem, and then his troubles ceased (Seforno). Jacob did not publicize the faith by calling out in the name of HaShem, because he was a scholar (Seforno). Ramban says that Jacob focused internally on building the Jewish tribes as a light to all people.
Isaac thought that he would build the tribes of the Jewish nation, but God was telling Isaac that the time was not ready for that path, but for continuing Abraham’s path. The blessings in the merit of Abraham told Isaac that he should continue in Abraham’s path.
Bereishit (26:13), “And the man became great, and he grew constantly greater until he had grown very great. (26:14) And he had possessions of sheep and possessions of cattle and much production, and the Philistines envied him. (26:15) And all the wells that his father’s servants had dug in the days of Abraham his father the Philistines stopped them up and filled them with earth. (26:16) And Abimelech said to Isaac, Go away from us, for you have become much stronger than we. (26:17) And Isaac went away from there, and he encamped in the valley of Gerar and dwelt there. (26:18) And Isaac again dug the wells of water which they had dug in the days of his father, Abraham, and the Philistines had stopped them up after Abraham’s death; and he gave them names like the names that his father had given them.”
Isaac re-digging the wells of Abraham carries the same idea that Isaac needed to continue in Abraham’s path. Verse (26:16) fits before verse (26:15), but the Torah is teaching us why God wanted Isaac banished, so that he should re-dig the wells of Abraham and continue in his path.