Verse 16. - The testimony which I will give thee, is undoubtedly the Decalogue, or in other words, the two tables of stone, written with the finger of God, and forming his testimony against sin. (Compare Deuteronomy 31:26, 27.) The main intention of the ark was to be a repository in which the two tables should be laid up.
25:10-22 The ark was a chest, overlaid with gold, in which the two tables of the law were to be kept. These tables are called the testimony; God in them testified his will. This law was a testimony to the Israelites, to direct them in their duty, and would be a testimony against them, if they transgressed. This ark was placed in the holy of holies; the blood of the sacrifices was sprinkled, and the incense burned, before it, by the high priest; and above it appeared the visible glory, which was the symbol of the Divine presence. This was a type of Christ in his sinless nature, which saw no corruption, in personal union with his Divine nature, atoning for our sins against it, by his death. The cherubim of gold looked one towards another, and both looked downward toward the ark. It denotes the angels' attendance on the Redeemer, their readiness to do his will, their presence in the assemblies of saints, and their desire to look into the mysteries of the gospel. It was covered with a covering of gold, called the mercy-seat. God is said to dwell, or sit between the cherubim, on the mercy-seat. There he would give his law, and hear supplicants, as a prince on his throne.
And thou shall put into the ark the testimony that I shall give thee. Which was the principal use of it: by the "testimony" is meant the law, written on two tables of stone; so called, because it was a testification of the mind and will of God, what he would have done or omitted; and as the Israelites had declared their approbation of it, and assent unto it, and had promised obedience to it, therefore, should they transgress it, it would be a testimony against them: now this was put into the ark, and preserved there, see Deuteronomy 10:1, which may signify that the law was in the heart of Christ, and which he undertook to fulfil, and with pleasure did it; that he is become the fulfilling end of the law for righteousness to them that believe in him; and that it remains with him as a rule of walk and conversation to his people, so far as it is of a moral, holy, and spiritual nature.