Many Bible teachers use the conversion of Cornelius in Acts 10 as an example of how sinners are saved in this age. They believe that Cornelius was baptized into the Body of Christ as a result of hearing and believing Peter's message. Let's work through Acts 10 and see whether these things are so.
Acts 9:32 through 10:48 records events in the ministry of the apostle Peter that took place outside of Jerusalem, but still within the land of Israel. As far as the record is concerned, at this point Peter is still operating under the kingdom program of Israel and does not yet know about the new revelations that Christ gave to Paul concerning the Body of Christ.
It is possible that when Saul of Tarsus met with Peter in Jerusalem three years after his conversion that he told him Christ had sent him to the Gentiles. The Lord had already told Ananias (a devout man according to the law) that Saul was a chosen vessel to bear His name before the Gentiles (Acts 9:15). But I do not believe that Saul told him about the revelations that Christ had given him in Arabia because:
1. He did not have time to discuss such major revelations during a brief (15 days) and busy visit ("coming in and going out," Acts 9:28)?
2. The record does not say that he discussed such matters.
3. It seems clear that it is not until Acts 15 that the apostles in Jerusalem begin to understand some things about Paul's ministry among the Gentiles (Gal. 2:1-2, 9).
During the meeting that is recorded in Acts 15 God used the salvation of the Gentile household of Cornelius in Acts 10 to convince the Jewish apostles that Paul's ministry among the Gentiles was according to the will of God. Although there are some new things that take place in Acts 10 that had not taken place before, there is no indication that Peter understood that a new dispensation had begun.
In Acts 10 (ten is the # for Gentiles, e.g. Gen. 10 contains genealogy of Gentile nations) the Lord sends Peter to preach to the Gentile household of Cornelius. This is a big deal because up to this point the Jewish apostles had not been preaching to uncircumcised Gentiles. Their ministry has been to "the Jews only" (Acts 11:19). In light of Matt. 28:19, why would it take a special vision from God to get Peter to go preach to some Gentiles?
The issue with Peter was not so much about preaching to Gentiles as it was about keeping company and eating with uncircumcised Gentiles (Acts 11:1-4, 17b). Circumcision was a token of the covenant between God and Abraham. To be uncircumcised was to be unclean and cut off from the blessings of the covenant. If Peter had understood the revelation of the mystery concerning the Body of Christ he would not have had a problem going to the house of an uncircumcised Gentile (Col. 3:11)! It is important to understand that Gentile salvation is not exclusive to the Grace Age. Gentiles could be saved in the OT, but only through and in connection with Israel (Gen. 12:1-3). Many Gentiles will be saved in the tribulation period and Kingdom Age. According to the kingdom program of Israel, Gentiles are to be saved through the rise and instrumentality of Israel (Isa. 60:1-5; Zech. 8:22-23).
The reason that the Jewish apostles had not yet preached to the Gentiles was not due to stubborn prejudice (they were filled with Holy Ghost and obedient despite persecution), but because Jerusalem had not yet repented (Lk. 24:47; Acts 1:8). The Jewish church did not have any problem with Gentiles getting saved (Acts 11:18).
The distinct thing about Gentiles being saved in this present age is that they are being saved and blessed WITHOUT Israel (Rom. 11:11-15, 25). Under Paul's ministry, idol-worshipping and uncircumcised Gentiles who could care less about the Jews can be saved by grace without works required and baptized into the spiritual Body of Christ.
Outline of Acts 10
I. The vision of Cornelius (vs.1-8)
II. The vision of Peter (vs.9-18)
III. Peter goes to the house of Cornelius in Caesarea (vs.19-33)
IV. Peter's message (vs.34-43)
V. The Gentiles baptized with the Holy Ghost and water (vs.44-48)
It is interesting to see how God worked separately with Cornelius and Peter and then in perfect timing brought them together. This chapter contains visions, the appearance of an angel, and sign gift of tongues- all of which was common during the Acts period but are not things we will experience today.