Exodus 31:18 - Joseph Benson’s Commentary on the Old and New Testaments

He gave unto Moses the two tables of testimony After his forty days' stay upon the mount, God dismissed him, giving him the ten articles of the moral law, written upon two tables of stone, to be delivered to the people, and to be laid up in the ark, as the standing record of the divine will relating to the principal branches of their duty. In the most ancient times, it must be observed, laws were wont to be engraven upon tables of brass, marble, wood, &c. These tables of stone, it appears, were not prepared by Moses, but probably by the ministry of angels. They were written with the finger of God That is, by his will and power immediately, without the use of any instrument. They were written in two tables, being designed to direct us in our duty toward God and toward man. They were called tables of testimony, because this written law testified the will of God concerning them, and would be a testimony against them, if they were disobedient.