Because the Lord blessed Isaac

Genesis 26:1-35
Isaac did the same thing as his father Abraham said to Amimelech that his wide is his sister. For he afraid he might lose his life on account of her.
Gerar is the place to Egypt, because God didn't allow Isaac went to Egypt for the famine, so he stayed in Gerar.
Philitstines stopped up well that was his father had dig, filling them with earth.
Isaac's servants dug in the valley and discovered a well of fresh water there. But the herdsmen of Gerar quarreled with Isaac's herdsmen and said "The water is outs!" Then they move on from there and dug another well Same quarrel rose again. Isaac moved on from there and dug another well, and no one quarreled over it. He called it Rehoborh, saying "Now the Lord has given us room and we will flourish in the land." He went up to Beersheba. He dug well and found water there. Beersheba means "We've found water"
Isaac had dug 4 wells in his life, plus he reopened the well that had been dug in the time of his father, he dug 5 well.
Abimelech said to Isaac that "We saw clearly that the Lord was with you." Isaac became rich and his wealth continue to grow because the Lord blessed him.
Why?
Isaac didn't quarrel with Abimelech or God, he was move on and dig another well until no one quarreled over it. More important is the Lord blessed him.
Famine uproots Isaac from the Negeb, but he goes north to Gerar, not south to Egypt.
He adopts the same ruse over Rebecca that his father had done with Sarah; but Rebecca is not taken from him. Like most of us, Isaac vacillates 動搖 between faith and fear, needing God's repeated reassurance: "I am with you... do not be afraid. I shall bless you."
Abimelech offers peace with honour, but there is bitter grief at home. In marrying Judith, the Hittite, Esau makes another wrong choice.
Life of Issac is moving on and dig another well, he did not argue with others, but the Lord blesses him. It seems weakness but the faith is strong.
How?
Under the blessing of the Lord I don't fear or afraid, for the blessing from the Lord.