John Wesley on Exodus 25:10

The ark was a chest or coffer, in which the two tables of the law, written with the finger of God, were to be deposited. If the Jewish cubit was, as some learned men compute three inches longer than our half - yard, (twenty one inches in all) this chest or cabinet was about fifty - two inches long, thirty - one broad and thirty one deep; it was overlaid within and without with thin plates of gold; it had a crown, or cornish of gold round it; rings and staves to carry it with; and in it he must put the testimony. The tables of the law are called the testimony, because God did in them testify his will; his giving them that law was in token of his favour to them, and their acceptance of it was in token of their subjection to him. This law was a testimony to them to direct them in their duty, and would be a testimony against them if they transgressed. The ark is called the ark of the testimony, Exo 30:6, and the tabernacle, the tabernacle of the testimony, Num 10:11. The tables of the law were carefully preserved in the ark, to teach us to make much of the word of God, and to hide it in our inmost thoughts, as the ark was placed in the holy of holies. It intimates likewise the care which divine providence ever did, and ever will take to preserve the records of divine revelation in the church, so that even in the latter days there shall be seen in his temple the ark of his testament. See Rev 11:19.