Then Isaac dug again the wells of water which had been dug in the days of his father Abraham, for the Philistines had stopped them up after the death of Abraham; and he gave them the same names which his father had given them. But when Isaac’s servants dug in the valley and found there a well of flowing water, the herdsmen of Gerar quarreled with the herdsmen of Isaac, saying, “The water is ours!” So he named the well Esek, because they contended with him. Then they dug another well, and they quarreled over it too, so he named it Sitnah. He moved away from there and dug another well, and they did not quarrel over it; so he named it Rehoboth, for he said, “At last the Lord has made room for us, and we will be fruitful in the land.” (Genesis 26:18-22).
Now recall that God had commanded Isaac to stay in the land of Gerar because He would bless Isaac and give this land to him and his descendants:
Stay in this land for a while, and I will be with you and will bless you. For to you and your descendants I will give all these lands and will confirm the oath I swore to your father Abraham... So Isaac stayed in Gerar (Genesis 26:3,6).
Instead of fighting the Philistines, which they would later do in generations of wars, Isaac chose to acquiese and move on. He trusted in the promise of God and waited on God's time. Ohe might wonder why he didn't trust God with respect to Rebekah when he first entered the land.
Now, unfortunately, as is often the case in Hebrew literature, events are described without any moral commentary. The expectation is that the careful student will discern and apply the appropriate moral principles from other texts to each event. Thus, there is no divine rebuke for Isaac's lying, nor for the deceptions of Jacob and Rebekah. Greater violations than these, even mass murder, will be forthcoming but still without narrative commentary on the morality. Some have suggested that these all justify the idea that "the ends justify the means," but I think that would be to misinterpret and misapply these texts. While there is no condemnation of the immoral actions, there is also no commendation of them.
Now, in the case of Isaac's handling of the controversy over these wells, we are told that when he finally found a well that was undisputed by the Philistines, God visited him:
That night the Lord appeared to him and said, “I am the God of your father Abraham. Do not be afraid, for I am with you; I will bless you and will increase the number of your descendants for the sake of my servant Abraham.” (Genesis 26:24).
While there is no direct word that what Isaac did in not fighting with the Philistines was right, I consider this an indirect affirmation of Isaac's trusting the Lord and obeying Him in staying in the land.
Perhaps there is a principle here that is affirmed by Jesus in the Sermon on the Mount:
“You have heard that it was said, ‘Eye for eye, and tooth for tooth.' But I tell you, Do not resist an evil person. If someone strikes you on the right cheek, turn to him the other also. And if someone wants to sue you and take your tunic, let him have your cloak as well. If someone forces you to go one mile, go with him two miles. Give to the one who asks you, and do not turn away from the one who wants to borrow from you (Matthew 5:38-42).
Jesus commands us, "Do not resist an evil person." How often we do just the opposite. Now, we do it in the name of "justice," first for ourselves, and then for anyone else that might be unjustly treated. I wonder if Jesus thought of this? I wonder if Isaac thought of this? I think sometimes we are more concerned with defending our "rights" and sticking it to those that would stick us than we are to trusting God and honoring His command. Paul also has something to say in this regard:
If any of you has a dispute with another, dare he take it before the ungodly for judgment instead of before the saints? Do you not know that the saints will judge the world? And if you are to judge the world, are you not competent to judge trivial cases? Do you not know that we will judge angels? How much more the things of this life! Therefore, if you have disputes about such matters, appoint as judges even men of little account in the church! I say this to shame you. Is it possible that there is nobody among you wise enough to judge a dispute between believers? But instead, one brother goes to law against another—and this in front of unbelievers! The very fact that you have lawsuits among you means you have been completely defeated already. Why not rather be wronged? Why not rather be cheated? Instead, you yourselves cheat and do wrong, and you do this to your brothers (1 Corinthians 6:1-8).
While Paul is speaking primarily about lawsuits involving Christians, I think there is a larger principle here, namely, honoring God, even God's priorities over worldly affairs. Again and again we are told that this world is passing away, yet we are so vigorously trying to hold on to it.
So, should Isaac have fought with the Philistines over the wells the Israelites dug? No. I believe he did the right thing. Even though they put the labor in digging the wells, it was good for them to trust God and move on, waiting for God's timing in providing for them.