God prevented Isaac from leaving the Promised Land and renewed the covenant with him, but then He had to protect Rebekah when Isaac lied about his relationship with her to Abimelech. [source][source][source]
"In the short span of one chapter, the writer shows how the whole of the life of Isaac was a rehearsal of that which happened to Abraham. Thus the lesson that is conveyed is that God"s faithfulness in the past can be counted on in the present and the future. What he has done for the fathers, he will also do for the sons." [1][source]
Whereas the events of Isaac"s life repeated those of Abraham"s on several occasions, God dealt with Isaac differently and in harmony with his individual character. The many parallels between this chapter and the story of Abraham (esp. chs12-14,20-21) show that the writer wanted the reader to compare and contrast the two men. [2][source]
"The figure of even a great man may be dwarfed by comparison with that of a distinguished father or of a famous son. Thus the character of Isaac is overshadowed by the majesty of Abraham and the dramatic interest of Jacob. There was a third factor which diminished the importance of Isaac; he was the husband of a clever and masterful wife. No matter how exciting the scene in which he may appear, he is always assigned to a minor part. At least, by contrast with these other actors, his role in life was prosaic, uneventful, obscure." [3][source]
"The chapter before us is full of illustrations of how difficulties should and should not be met." [4][source]