Or HaChaim on Genesis 23:13/אור החיים על בראשית כ״ג:י״ג

1 וידבר אל עפרון, "He said to Efron, etc." The use of the word אך indicated Abraham's desire to proceed with a minimum of further discussion.

2נתתי כסף השדה, "I have given the money for the field." Even if Efron had decided to give him the field as a gift, Abraham begged Efron to accept the money from him. If so, Abraham would accept the field as a gift.