וַיֹּ֤אמֶר אֲרַ֙וְנָה֙ אֶל־דָּוִ֔ד יִקַּ֥ח וְיַ֛עַל אֲדֹנִ֥י הַמֶּ֖לֶךְ הַטּ֣וֹב בעינו [בְּעֵינָ֑יו] רְאֵה֙ הַבָּקָ֣ר לָעֹלָ֔ה וְהַמֹּרִגִּ֛ים וּכְלֵ֥י הַבָּקָ֖ר לָעֵצִֽים׃
And Araunah said unto David: ‘Let my lord the king take and offer up what seemeth good unto him; behold the oxen for the burnt-offering, and the threshing-instruments and the furniture of the oxen for the wood.’
Ibn Ezra
למורג A threshing instrument. It is well known.22A.V., "Sharp." Comp. המוריגים threshing instruments (2 Sam. 24:22).
Rabbeinu Bahya
Avraham did not want to accept any gifts from him but to pay full value, בכסף מלא, as is the custom of righteous people. We find that King David (Samuel II chapter 24) also did not want to accept any gifts and paid handsomely for the threshing ground of Aravnah the Jebusite, although offered the site plus animals to serve as sacrifices as well the animals’ yokes to serve as fire-wood. David paid 50 shekels for the threshing ground plus the animals and their yokes as he did not want to appear cheap in the eyes of G’d (Samuel II 24,24).