"Thus saith the LORD, Where is the bill of your mother's divorcement, whom I have put away? or which of my creditors is it to whom I have sold you? Behold, for your iniquities have ye sold yourselves, and for your transgressions is your mother put away." (Isaiah 50:1)
The Mosaic Law gave room for a man to divorce his wife due to some moral impurity (Deuteronomy 24:1). Using this example, the Lord challenges Israel to consider her situation. God had not distanced Himself from Israel; Israel had distanced herself from God. She was, as Hosea prophesied, the harlot who had sold herself in spite of the love shown to her by a faithful husband (Hosea 3:1-3). God is making it clear that He has not permanently put aside His chosen people (Romans 11:1). An official bill of divorcement did not exist then, and it does not exist now. The Lord is not the instigator of broken relationships; He is focused on the restoration of relationships (Genesis 3:8-9). When a rift exists between God and an individual, the fault is always with the individual.
"Wherefore, when I came, was there no man? when I called, was there none to answer? Is my hand shortened at all, that it cannot redeem? or have I no power to deliver? behold, at my rebuke I dry up the sea, I make the rivers a wilderness: their fish stinketh, because there is no water, and dieth for thirst. I clothe the heavens with blackness, and I make sackcloth their covering. The Lord GOD hath given me the tongue of the learned, that I should know how to speak a word in season to him that is weary: he wakeneth morning by morning, he wakeneth mine ear to hear as the learned." (Isaiah 50:2-4)
The wherefore is asking a question. God is saying, "Why is it, when I came, there was no man? Why is it, when I called, there was no one to answer?" Such a sought-after people should have been ready to hear and to obey; but instead, they were rebellious. Principally speaking, the Christian should be ready to hear and to obey because he is without excuse having the indwelling Holy Spirit and the written Word of God.
God reminds His readers that He is well able to save the one who trusts Him. In the Hebrew text, the phrase shortened at all is emphatic. In no way is God incapacitated and unable to overcome. The word for deliver carries with it the idea of snatching away. Effortlessly, God snatches the trusting soul out of the mouth of his predator; but the wicked are left to experience the results of their faithlessness.
The last verse may be applied in a near sense to Isaiah himself and in a fuller sense to the Messiah. As Christ was able to speak the proper words at the proper time, even so had God enabled Isaiah to speak what was appropriate for the occasion. The disobedient ear rejects God's words as burdensome things; but the righteous man receives them as cool water is received by an exhausted laborer. Morning by morning speaks of God's daily supply. Each day, the power to continue the Lord's work was renewed for Isaiah. Applying the words to Christ Himself, the true Servant was in constant communion with His Master as He flawlessly fulfilled His will here on earth.