This is an important consideration in mission work. Let me quickly add that rejection may not just result from proclaiming the gospel, as much rejection comes from “Christians” when they are presented a biblical model of ministry. In either case, rejection is real, hard to bear, and may cause doubts. In this respect, I quote from Rolland Allen, Missionary Methods – St. Paul’s or Ours?
“The possibility of rejection was ever present. Paul did not establish himself in a place and go on preaching for years to men who refused to act on his teaching. When once he had brought them to a point where decision was clear, he demanded that they should make their choice. If they rejected him, he rejected them. The ‘shaking of the lap’ (Acts 18:6), the ‘shaking of the dust from the feet’ (Mathew 10:14), the refusal to teach those who refuse to act on the teaching, was a vital part of the Pauline presentation of the Gospel. He did not simply ‘go away’, he openly rejected those who showed themselves unworthy of his teaching.” (Eerdmans Publishing, page 75).
This is a serious question in any avenue of ministry. We have often said that we want to work where God is already at work because He has prepared the heart to receive teaching from the Holy Spirit and the Word of God. The difference is between wanting to be effective in the Spirit’s power or just going through the motions of missions and ministry. One glorifies God, the other exalts man.