Proselytes were common in the days of the apostles. Acts 2:10 records their presence, with the Jews, in Jerusalem on Pentecost. Nicolas, "a proselyte from Antioch," is numbered in Acts 6:5 as an original deacon. Finally, Acts 13:43, mentions "devout proselytes" who followed Paul in Antioch. In context, these clearly refer to Gentile proselytes to Judaism.
Indeed, Paul's problems with the circumcision party had its roots in the widespread Jewish practice of proselytism in those days. The members of this party - almost certainly (misguided) members of God's church - followed Paul from city to city, telling Gentile converts of their need for physical circumcision. They took their cues from Exodus 12:48 and other scriptures. These Jews were men of their age, and therefore took no exception to the practice of proselytism. Also, they apparently accepted the validity of Paul's commission to carry Christ's "name before Gentiles" (Acts 9:15). Their only issue was physical circumcision. As a result of this controversy, the apostles had to redefine circumcision in its proper New Covenant terms.
In the New Testament, God clearly commissioned some to preach the gospel of God's Kingdom actively. Paul received such a commission, as Acts 9:15 clearly relates. Christ also commissioned His other apostles to "go therefore and make disciples of all the nations . . ." (Matthew 28:19). These commissions have their parallel in the commissions received by the Old Testament prophets. Examples include the prophets Isaiah (Isaiah 6), Jeremiah (Jeremiah 1) and Jonah (Jonah 1).
It is important to recognize, though, that neither the Old Testament commissions to the prophets nor the New Testament commissions to the apostles remove the responsibility on the part of the people to be examples. God has always used this means - the example of His people - as a fundamental method of reaching others. As one excellent New Testament example, notice I Thessalonians 1:7-9, where Paul lauds the converts in Thessalonica, pointing out the breadth of their example to other church congregations and to the world at large:
. . . so that you became examples to all in Macedonia and Achaia who believe. For from you the word of the Lord has sounded forth, not only in Macedonia and Achaia, but also in every place. Your faith toward God has gone out, so that we do not need to say anything. For they themselves declare concerning us what manner of entry we had to you, and how you turned to God from idols to serve the living and true God. . . .
So strong was their witness that Paul needed not "to say anything." These people certainly did not hide their light under a basket. Example can speak louder than preaching.