Verse 18. "With thee will I establish my covenant" - The word tyrb berith, from rb bar, to purify or cleanse, signifies properly a purification or purifier, (see on chap. 15.,) because in all covenants made between God and man, sin and sinfulness were ever supposed to be on man's side, and that God could not enter into any covenant or engagement with him without a purifier; hence, in all covenants, a sacrifice was offered for the removal of offenses, and the reconciliation of God to the sinner; and hence the word tyrb berith signifies not only a covenant, but also the sacrifice offered on the occasion, Exod. xxiv. 8; Psa. l. 5; and Jesus Christ, the great atonement and purifier, has the same word for his title, Isa. xlii. 6; xlix. 8; and Zech. ix. 11.
Almost all nations, in forming alliances, &c., made their covenants or contracts in the same way. A sacrifice was provided, its throat was cut, and its blood poured out before God; then the whole carcass was divided through the spinal marrow from the head to the rump; so as to make exactly two equal parts; these were placed opposite to each other, and the contracting parties passed between them, or entering at opposite ends met in the center, and there took the covenant oath. This is particularly referred to by Jeremiah, Jer. xxxiv. 18, 19, 20: "I will give the men (into the hands of their enemies, Jer. xxxiv. 20) that have transgressed my covenant, which have not performed the words of the covenant which they made before me, when they cut the calf in twain, and passed between the parts thereof," &c. See also Deut. xxix. 12.
A covenant, says Mr. Ainsworth, is a disposition of good things faithfully declared, which God here calls his, as arising from his grace towards Noah (ver. 8) and all men; but implying also conditions on man's part, and therefore is called our covenant, Zech. ix. 11. The apostles call it diaqhkh, a testament or disposition; and it is mixed of the properties both of covenant and testament, as the apostle shows, Heb. ix. 16, &c., and of both may be named a testamental covenant, whereby the disposing of God's favours and good things to us is declared. The covenant made with Noah signified, on God's part, that he should save Noah and his family from death by the ark. On Noah's part, that he should in faith and obedience make and enter into the ark- Thou shalt come into the ark, &c., so committing himself to God's preservation, Heb. xi. 7. And under this the covenant or testament of eternal salvation by Christ was also implied, the apostle testifying, 1 Pet. iii. 21, that the antitype, baptism, doth also now save us; for baptism is a seal of our salvation,