Do Genesis 21 and Genesis 26 Contradict?

In Genesis 21, it is written: "Therefore he called that place Beersheba, because there the two of them took an oath," (Genesis 21:31 NASB1995).

In Genesis 26, it is written: "So he called it Shibah; therefore the name of the city is Beersheba to this day," (Genesis 26:33 NASB1995).

According to some, this passage shows a contradiction between when the city of Beersheba received its name. In Genesis 21, Abraham made a covenant with Abimelech (Genesis 21:27) and named the city Beersheba (Genesis 21:31). In Genesis 26, it was Isaac who made a covenant with Abimelech (Genesis 26:28-30) and then named the city Beersheba (Genesis 26:33). There is, however, no contradiction. This merely seems to have been two separate events. As Dr. Kitchen explains: "That Abimelech of Gerar should have successive treaties with Abraham and Isaac is no more a 'doublet' than (e.g.) Talmi-Sharruma of Aleppo having successive treaties with two Hittite kings Mursi II and Muwatallis II," (Kitchen 345).

As the Keil and Delitzsch Commentary on the Old Testament states: "Therefore the city was called Beersheba." This derivation of the name does not shut the other (Genesis 21:31) out, but seems to confirm it. As the treaty made on oath between Abimelech and Isaac was only a renewal of his covenant concluded before with Abraham, so the name Beersheba was also renewed by the well Shebah," (Keil).

The problem with this criticism is the Bible specifically answers this issue: "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," (Genesis 26:18 NASB1995). Isaac merely renamed the well after repairing it (Kitchen 336); thus, Genesis does not contradict, this supposed contradiction merely comes from a poor reading of the text.

References:

Keil, C. F., & Delitzsch, F. (1920). Keil and Delitzsch Commentary on the Old Testament. Library of the Union Theological Seminary.

Kitchen, K. A.. On the Reliability of the Old Testament. United States, Eerdmans Publishing Company, 2006.