In Chapter 26 of Genesis, the character of Isaac is presented primarily as a son who is dedicated to the ideals and projects of his father Abraham.
The chapter begans with Isaac going to the land of the Philistines to escape the famine that was affected the land of Canaan; we can deduce from verse 2 that his real intent was to continue his travels all the way to Egypt. This is similar to what Abraham had done on a previous occassion of famine (see Genesis 12).
God, however, does not permit Isaac to leave the land of Canaan, because He has promised it to Abraham as an inheritance:
Sojourn in this land, and I will be with you, and will bless you; for to you and to your descendants I will give all these lands, and I will fulfil the oath which I swore to Abraham your father.
In other words, Isaac must stay in Canaan in order to carry out the mission that was assigned to his father, Abraham.
While living in Gerar, in the land of the Philistines, "the men of the place" ask Isaac about the availability of his wife, Rebecca. Afraid that these men may kill him "for the sake of Rebecca," Isaac answers that she is not his wife, but his sister. It is obvious that he borrowed this strategy from his father, Abraham, who used it twice (see Genesis 12 and 20).
Although we might question the fairness of this strategy, God seems to approve, for soon after Isaac is blessed with great wealth, so much so that the Philistines envy him. Due to their envy, the Philistines begin plugging up the wells that had been dug previously under Abraham's direction. Isaac, as usual, is dedicated to his father's projects:
And Isaac dug again the wells of water which had been dug in the days of Abraham his father; for the Philistines had stopped them after the death of Abraham; and he gave them the names which his father had given them.