Here are some great words of wisdom from Charles Spurgeon.
"One night the Lord spoke to Paul in a vision: Do not be afraid; keep on speaking, do not be silent. For I am with you, and no one is going to attack and harm you, because I have many people in this city." Acts 18:9-10 This should be a great encouragement to evangelize, since God has . . . among the vilest of the vile, among the most reprobate, among the most debauched and drunken --an elect people who must be saved! When you take the Word to them, you do so because God has ordained you to be the messenger of life to their souls, and they must receive it--for so the decree of predestination runs. They are as much redeemed by Christ's blood, as the saints before the eternal throne! They are Christ's property--yet perhaps they are at present, lovers of the ale-house and haters of holiness. But if Jesus Christ has purchased them--He will have them. God is not unfaithful to forget the price which His Son has paid. He will not allow His substitutionary sacrifice to be in any case an ineffectual, dead thing. Tens of thousands of redeemed ones are not regenerated yet--but regenerated they must be! This is our comfort when we go forth to them with the quickening Word of God. Nay, more, these ungodly ones are prayed for by Christ before the throne. "My prayer is not for them alone," says the great Intercessor, "I pray also for those who will believe in Me through their message." Poor, ignorant souls, they do not pray for themselves--but Jesus prays for them! Their names are on His breastplate, and before long they must bow their stubborn knee, breathing the penitential sigh before the throne of grace. The predestined moment has not yet struck! But when it comes, they shall obey--for God will have His own redeemed people! They must obey--for the Spirit is not to be withstood when He comes forth with the fullness of His saving power. They must become the willing servants of the living God. "My people shall be willing in the day of My power." "He shall see of the travail of His soul, and be satisfied."