I did not say to the offspring of Jacob, 'seek me in vain.'Isaiah 45:19
We can gain a great deal of comfort by considering what God has not said. What He has said is full of comfort and delight; but what He has not said is scarcely less rich in consolation. It was what God had not said that preserved the kingdom of Israel in the days of Jeroboam the son of Joash, for "the LORD had not said that he would blot out the name of Israel from under heaven" (2 Kings 14:27). In our text we have an assurance that God will answer prayer because He "did not say to the offspring of Jacob, 'Seek me in vain.'"
Those of you who are prone to self-condemnation should remember that, lest your doubts and fears say what they will, if God has not cut you off from mercy, there is no need for despair: Even the voice of conscience carries little weight if it is not seconded by the voice of God. We should tremble at what God has said! But do not allow your rambling thoughts to overwhelm you with despondency and sinful despair. Many timid persons have been vexed by the suspicion that there may be something in God's decree that shuts them out from hope, but we have here a complete rebuttal of that troublesome fear, for no true seeker can be decreed to wrath. "I did not speak in secret, in a land of darkness; I did not say [even in the secret of my unsearchable decree] . . . , 'Seek me in vain.'"
God has clearly revealed that He will hear the prayer of those who call upon Him, and that declaration cannot be contradicted. He has spoken so firmly, so truthfully, so righteously that there can be no room for doubt. He does not reveal His mind in unintelligible words, but He speaks plainly and positively. "Everyone who asks receives."1 Doubter, believe this sure truth—that prayer must and will be heard, and that never, even in the secrets of eternity, has the Lord said to any living soul, "Seek me in vain."
1) Matthew 7:8