"There was a certain man in Caesarea called Cornelius, a centurion of what was called the Italian Regiment, a devout man and one who feared God with all his household, who gave alms generously to people, and prayed to God always. About the ninth hour of the day he saw clearly in a vision an angel of God coming in and saying to him, 'Cornelius.' And when he observed him, he was afraid, and said, 'What is it, lord?' So he said to him, 'Your prayers and your alms have come up for a memorial before God. Now send men to Joppa, and send for Simon whose surname is Peter. He is lodging with Simon, a tanner, whose house is by the sea. He will tell you what you must do.' And when the angel who spoke to him had departed, Cornelius called two of his household servants and a devout soldier from among those who waited on him continually. So when he had explained all these things to them, he sent them to Joppa" (Acts 10:1-8)
Here Luke introduces us to Cornelius, a Roman soldier living in Caesarea (approximately 30 miles away from Joppa). Specifically, he was a centurion (i.e., a commander responsible for 100 soldiers). As the narrative unfolds, it becomes clear that Cornelius was a Gentile, not a Jew. Clearly, Cornelius was a very religious-minded person. He was not committed to an idol but to the one, true God, having a healthy fear and respect for Him. He gave generously to the needy and prayed to God daily. His entire household (which would include his family as well as his servants) had a similar mindset toward God. Cornelius had a strong influence for much good and had a very positive reputation. This inspired description of Cornelius shows him to be a "good moral person." But, more significantly, it shows him to be a seeker (cf. Matt. 7:7,8). Cornelius is a remarkable man! Interestingly, the amount of space Luke uses to tell us of Cornelius' conversion (the first Gentile convert) tells us how important it is to God.
Cornelius had a vision one afternoon where an angel of God spoke to him. Cornelius was informed that his prayers and benevolence had caught God's attention, so to speak. Literally, they had come up before God as a "memorial" or as a remembrance. It was time for the Gentiles to be offered the gospel; God had heard his prayers and would answer them now. Cornelius was instructed to send for Peter who would come and tell him what he "must do." At the completion of the vision, Cornelius obeyed immediately, sending three men to Joppa to go invite Peter to come to his home and teach him.
It should be observed that at this point in the narrative, despite Cornelius' "moral goodness," he is not in the position he needs to be in spiritually! He needs to be converted to Christ! Being devout, respectful to God, generous, and prayerful are necessary but not sufficient for salvation! In the Christian dispensation, good, sincere, people are still lost without Christ. The angel informed him that there were some things that he "must do" (10:6). Peter would instruct Cornelius of these matters during their dialogue and issue an important command (cf. 10:47,48). Just like Saul of Tarsus, Cornelius needed someone to come and speak to him the words by which he and his household would be saved (cf. 11:14). Even though Saul spoke with the Lord on the road to Damascus and Cornelius spoke with an angel, both men were dependent upon mortals to tell them what they needed to do to be saved! God made it possible for the seeker and teacher to get together (and He still does), but God has given His followers the responsibility to teach others His word! Supernatural interventions never supersede the indispensable work of the human agent. Just like the Ethiopian eunuch, Cornelius was a God-fearing man who was searching for the Lord's will. Both men would be saved when they learned the truth, believed it, and obeyed it. Such is still true today.