Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
"AND the tables were the work of God" (Exod. xxxii. 16), that is to say, they were the product of nature, not of art; for all natural things are called "the work of the Lord," e.g., "These see the works of the Lord" (Ps. cvii. 24); and the description of the several things in nature, as plants, animals, winds, rain, etc., is followed by the exclamation, "O Lord, how manifold are thy works!" (Ps. civ. 24). Still more striking is the relation between God and His creatures, as expressed in the phrase, "The cedars of Lebanon, which he hath planted" (ib. 16); the cedars being the product of nature, and not of art, are described as having been planted by the Lord. Similarly we explain, "And the writing was the writing of God" (Exod. xxxii. 16); the relation in which the writing stood to God has already been defined in the words "written with the finger of God" (ib. xxxi. 18), and the meaning of this phrase is the same as that of "the work of thy fingers" (Ps. viii. 4). this being said of the heavens; of the latter it has been stated distinctly that they were made by a word; comp. "By the word of the Lord were the heavens made" (ib. xxxiii. 6). Hence you learn that in the Bible, the creation of a thing is figuratively expressed by terms denoting "word" and "speech" The same thing which according to one passage has been made by the word, is represented in another passage as made by the "finger of God." The phrase "written by the finger of God" is therefore identical with "written by the word of God"; and if the latter phrase had been used, it would have been equal to "written by the will and desire of God?" Onkelos adopted in this place a strange explanation, and rendered the words literally "written by the finger of the Lord"; he thought that "the finger" was a certain thing ascribed to God; so that "the finger of the Lord" is to be interpreted in the same way as "the mountain of God" (Exod. iii. 1), "the rod of God" (ib. iv. 20), that is, as being an instrument created by Him, which by His will engraved the writing on the tables. I cannot see why Onkelos preferred this explanation. It would have been more reasonable to say "written by the word of the Lord," in imitation of the verse "By the word of the Lord the heavens were made?" Or was the creation of the writing on the tables more difficult than the creation of the stars in the spheres? As the latter were made by the direct will of God, not by means of an instrument, the writing may also have been produced by His direct will, not by means
of an instrument. You know what the Mishnah says, "Ten things were created on Friday in the twilight of the evening," and "the writing" is one of the ten things. This shows how generally it was assumed by our forefathers that the writing of the tables was produced in the same manner as the rest of the creation, as we have shown in our Commentary on the Mishnah (Aboth, v. 6).