What is God calling Christians to do? We are simply to be found faithful in the task of delivering the Gospel message. We are to bring the gospel into our workplaces, friendships, and families, to whomever and wherever. All that is required is to look to where God has placed us and simply to be found faithful to the task of proclaiming the good news to those who are dead in their sins. It requires that we not be ashamed of the good news of the gospel, which includes not being ashamed of the bad news of God’s judgment against sin.
Whatever the result of that proclamation of the gospel may be, whether a hardening or a softening of the heart, God effectually uses this message for His purposes.
Not every instance of proclaiming a message of repentance is designed by God to bring the people who hear it to repentance and faith. In fact, Scripture often demonstrates the opposite is true—that the proclamation serves to condemn the recipients rather than restore them. A great example of this is found in the commissioning of the prophet Isaiah:
Then I heard the voice of the Lord, saying, “Whom shall I send, and who will go for us?” Then I said, “Here am I. Send me!” He said,
“Go and tell these people: Keep on listening, but do not perceive; keep on looking, but do not understand. Render the hearts of these people insensitive, their ears dull, and their eyes dim, otherwise they might see with their eyes, hear with their ears, understand with their hearts, and return and be healed.” Then I said, “Lord, how long?” and He answered, “Until cities are devastated and without inhabitants, houses are without people and the land is utterly desolate, the Lord has removed men far away, and the forsaken places are many in the midst of the land. Yet there will be a tenth portion in it, and it will again be subject to burning, like a terebinth or an oak whose stump remains when it is felled. The holy seed is its stump” Isaiah 6:8-13
As Brevard Childs ( Isaiah. Westminster John Knox Press, (2001): p56). puts it, “Isaiah, the prophet is to be the executor of death, the guarantor of complete hardening. His very proclamation is to ensure that Israel will not turn and repent.” How would you like to be called by God to deliver that message?

“If sinners will be damned, at least let them leap to Hell over our bodies. And if they will perish in the Lake of Fire, let them perish with our arms about their knees, imploring them to stay. If Hell must be filled, at least let it be filled in the teeth of our exertions, and let not one go there unwarned and unprayed for.” Charles Spurgeon
We may not necessarily like the implications of God using our proclamation of judgment and salvation to effectively harden an individual’s heart. We may not believe the implications of this are even fair—but we ought to remember in the midst of everything that we don’t want fair because our idea of what’s fair doesn’t square with God’s.
What’s fair is God condemning every man, woman, and child to eternal destruction in the Lake of Fire. What’s fair is that the only blameless One to have ever existed would not be put to the cross to pay for the sins of others. What you and I desire is mercy and grace, because mercy is not giving people what they deserve, which is condemnation, and grace is giving people what they don’t deserve, which is no condemnation. The gospel is a scandal to the world because it sees the murderer, rapist, racist, and the like, on equal footing with the sweet old lady who doesn’t confess Christ—and offers them all the same grace of God in Christ. What that very simply means is that the gospel is not barred from anyone on the basis of their own doing or choosing, but rather, on the sovereign choice of God Himself. If those who struggle with evangelizing were to focus on the sovereignty of God in evangelism, it would free many a burdened soul up to take joy in the work that God has given them, realizing that whether the person they share the gospel with rejects or receives it, God is glorified in accomplishing His work through the preached word.
This post was extracted from an article by Grayson Gilbert, A Lesson from Isaiah on the Sovereignty of God in Evangelism July 23, 2020, http://www.patheos.com