While many assume that evangelism was an afterthought during the Reformation, Martin Bucer (1491-1551), the reformer of Strasbourg, demonstrates that this was not the case. His handbook on pastoral care, Concerning the True Care of Souls, is suffused with his concern for reaching the lost. In his interpretation of this passage, Bucer builds on Paul’s example as one who sought to share the gospel and argues that it is a minister’s role to faithfully and diligently help unbelievers find salvation.

1 Corinthians 9:19-23

Though I am free and belong to no one, I have made myself a slave to everyone, to win as many as possible. To the Jews I became like a Jew, to win the Jews. To those under the law I became like one under the law (though I myself am not under the law), so as to win those under the law. To those not having the law I became like one not having the law (though I am not free from God’s law but am under Christ’s law), so as to win those not having the law. To the weak I became weak, to win the weak. I have become all things to all people so that by all possible means I might save some. I do all this for the sake of the gospel, that I may share in its blessings. 

Commentary on 1 Corinthians 9:19-23

The faithful ministers of Christ are not to give up lightly on anyone, as long as people are still people and God’s creatures and have not shown themselves to be dogs by raging all the more against those who call them to the kingdom of heaven, the more faithfully such people want to assist them to find salvation; or in that the more attractively and gloriously the pearl of the holy gospel is presented to them, the more they despise it and trample it under foot. This is why the second point, the faithfulness, seriousness, and diligence with which the Lord desires his lambs to be sought, must be thoroughly taken to heart and faithfully considered. He desires that they should be sought wherever they are scattered, and sought with such seriousness and diligence that one should be ready to be all things to all people, as dear Paul was, and even to hazard one’s own life, as the Lord himself did, so that the lost lambs might be found and won.

1 Corinthians, ed. Scott M. Manetsch, Reformation Commentary on Scripture, NT vol. 9A, p.190.