The Church at Ephesus was established while Paul briefly passed by that way journeying to Jerusalem at the end of the second tour (Acts 18:19-21).
No mention of specific converts is made until those found in Acts 19:1-5. Paul did in Ephesus as he always did; he preached the word in the synagogue seeking to convert the Jews first. Later, he turned to the Gentile population (Acts 19:8-9).
Ephesus became Paul's third center of evangelism. In the beginning, it was Antioch in Syria. Later, it was Philippi in Macedonia. Now, it was Ephesus. Paul's work in the school of Tyrannus allowed him to spread the Word throughout all Asia (Acts 19:10). During the two years at Ephesus, churches of Christ were established in Laodicea, Heirapolis, Sardis, Pergamos, Thyatira, Smyrna, Philadelphia, Colosse and Troas (cf. Revelation 2 and 3; 2 Cor. 2:12).
The conversions at Ephesus are sometimes misused by those who hold the false doctrine that salvation occurs at the point of faith before and without water baptism. A favorite passage of these people is Ephesians 2:8-9, "For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: not of works lest any man should boast." Let's consider the evidence which the Scriptures reveal concerning their redemption. Specifically, let's see what the New Testament says about their baptism.
There is no debating about whether or not salvation is a matter of grace -- it is (Eph. 2:8). We are not saved by works of our own righteousness but according to God's mercy (Titus 3:5). The question is whether or not there are works of another class included within the realm of grace? Does the Bible teach there are "works" which exclude boasting consistent with divine grace?
The Bible says that Abraham was saved by "works" (Jam. 2:21-23). These were works of faith, that is, obedience to God which was rooted in and sprang forth from faith (Heb. 11:8, 17-19). There is no sense in which the works which Abraham did can be said to have been "his own works." He did not appoint the journey. He did not originate the sacrifice of his only son. God asked for these things and Abraham with implicit trust obeyed God.
Thus, we are urged to walk in the steps of Abraham's faith (Rom. 4:12). How can we so walk, if "doing" nullifies grace?
Peter clearly declares salvation is promised to him that fears God and works righteousness (Acts 10:34-35). Paul affirms that he preached in order to secure from others the "obedience of faith" (Rom. 1:5; 16:26). Such obedience is not inconsistent with grace, but establishes grace (Rom. 6:15-18).
Paul speaks very favorably of the Ephesians in his letter to them. He writes of their exalted position in Jesus Christ "in heavenly places" (Eph. 1:3, 20; 2:6) and of the Church which is the bride of Christ, and the fact that they are that Church which is the visible expression of the "manifold wisdom of God" (Eph. 3:10).
Now, the Ephesians were the inheritors of all the spiritual blessings in Christ (Eph. 1:3) when they trusted in Christ (Eph. 1:13). However, that faith could not exist apart from "the word of truth, the Gospel of your salvation." Their faith existed "after" they heard (cf. Rom. 10:17). Saving faith is always the result of hearing the Gospel.
The Ephesians were most certainly baptized (Acts 19:1-5). With respect to their baptism Paul said, "Christ loved the Church, and gave Himself for it; that He might sanctify and cleanse it with the washing of water by the word" (Eph. 5:-5, 26). What did Christ sanctify and cleanse? It was the Church. With what did Jesus sanctify and cleanse the Church? Jesus used two things in setting the Church apart in holiness: baptism and the Gospel.
Notice that it is "the washing of water," baptism (Acts 22:16), "through the word," the Gospel. Baptism is efficacious to our sanctification because God has revealed it (Mark 16:16; Acts 2:36-40).
Our faith is not in ourselves and what we have done (Titus 3:5), but rather it is in His mercy and what He has promised (Col. 2:12). The baptized believer is not trusting in himself so that he can boast and demand a reward as a matter of debt.
Similarly, Peter affirmed that baptism saves us "by the resurrection of Jesus Christ who is gone into heaven and is on the right hand of God" (1 Pet. 3:21-22). Clearly the saving power is not ourselves but the Resurrected Redeemer Who has all power in Heaven and in earth.
We are justified by grace through faith when we believe and obey the Gospel.