All people are ready to perish under the wrath of God by nature, for all are sinners, but very few know it. Isaiah is talking about men and women who are in danger and know it. They are, in their own apprehension of things, "ready to perish." A person is "ready to perish when he is convinced that he deserves to perish, feels that he must surely perish and senses that he is perishing. Being convinced of his own guilt and sin before a just and holy God, he comes to God by faith in Christ, crying, "Lord, save me, I am perishing!"
If you have been there, you know exactly what I mean. A sinner is "ready to perish" when he feels the wrath of God in his soul, when the sword of divine justice pricks his heart, causing him to seek the mercy of God in Christ. (Read Acts 2:36-38). We are not saved by feelings. And we must not look for a feeling. Look to Christ! Holy Spirit conviction is more than a feeling of guilt and remorse. But when the wrath of God seizes a sinner's heart and he is "ready to perish," he feels it in his soul!
This is the way God begins with those whom he has purposed to save. He first destroys our confidence in ourselves. Then he gives us confidence in Christ. God always wounds before he heals,strips before he clothes, abases before he exalts and slays before he makes alive. No one is ready for grace until he is "ready to perish." You will never come to Christ until you know that you are "ready to perish" without Christ. And if you are "ready to perish," you will come to Christ.