Isaiah 1:18

“Come now, and let us reason, together, saith the Lord, &c.] These words stand not in connection either with the preceding or following, but are to be read in a parenthesis, and are thrown in for the sake of the small remnant God had left among this wicked people, in order to comfort them, being distressed with sin. These, seeing their sins in their dreadful colours, and with all their aggravating circumstances, were ready to conclude that they were unpardonable; and, seeing God as an angry Judge, dared not come nigh him, but stood at a distance, fearing and expecting his vengeance to fall upon them, and therefore put away the promises, and refused to be comforted; when the Lord was pleased…”

“God deigns to argue the case with us, that all may see the just, nay, loving principle of His dealings with men (Isa 43:26). scarlet--the color of Jesus Christ's robe when bearing our "sins" (Mat 27:28). So Rahab's thread (Jos 2:18; compare Lev 14:4). The rabbins say that when the lot used to be taken, a scarlet fillet was bound on the scapegoat's head, and after the high priest had confessed his and the people's sins over it, the fillet became white: the miracle ceased, according to them, forty years before the destruction of Jerusalem, that is, exactly when Jesus Christ was crucified; a remarkable admission of adversaries. Hebrew for "scarlet" radically means double-dyed; so the deep-fixed…”

“Come now - This is addressed to the nation of Israel; and the same exhortation is made to all sinners. It is a solemn act on the part of God, submitting the claims and principles of his government to reason, on the supposition that men may see the propriety of his service, and of his plan. Let us reason together - ונוכחה venivākechâh from יכח yâkach, not used in Kal, but in Hiphil; meaning to show, to prove. Job 13:15 : ‘Surely I will prove my ways (righteous) before him;’ that is, I will justify my ways before him. Also to correct, reprove, convince, Job 32:12; to rebuke, reproach, censure, Job 6:25; to punish, Job 5:17; Proverbs 3:12; to judge, decide, Isaiah 11:3; to do justice, Isaiah…”

“1:18 God called his people to come and settle their dispute so that he could restore his covenant relationship with them. This required Judah to make a decision between obeying or turning away (1:19-20). Isaiah says their sins are like scarlet . . . they are red like crimson, the color of blood, which Judah had unjustly shed (1:15). • white as snow . . . white as wool: The people would be radically transformed—cleansed, purified, and made holy (see also Ps 51:7; Dan 7:9).”

“and let us: Isa 41:21, Isa 43:24-26; Sa1 12:7; Jer 2:5; Mic 6:2; Act 17:2, Act 18:4, Act 24:25 though your: Isa 44:22; Psa 51:7; Mic 7:18, Mic 7:19; Rom 5:20; Eph 1:6-8; Rev 7:14 Isaiah 1:19”

“The first leading division of the address is brought to a close, and Isa 1:18 contains the turning-point between the two parts into which it is divided. Hitherto Jehovah has spoken to His people in wrath. But His love began to move even in the admonitions in Isa 1:16, Isa 1:17. And now this love, which desired not Israel's destruction, but Israel's inward and outward salvation, breaks fully through. "O come, and let us reason together, saith Jehovah. If your sins come forth like scarlet cloth, they shall become white as snow; if they are red as crimson, they shall come forth like wool!" Jehovah here challenges Israel to a formal trial: nocach is thus used in a reciprocal sense, and with the…”