When Peter preached to Cornelius and his household, was repentance anywhere in his sermon? Is a person born again by faith and repentance, or by faith? I think that I was born again when God revealed His Son to me, and I believed in Him, am I completely wrong? I believed in Him first, then I believed His message of repentance. Can a born again Christian be saved if they do not continue to obey God's Word?
My seventy-seven year old father does not believe that God or Jesus exist. My father will never believe the message of repentance until he first believes in the messenger. I believe that my father would be born again if he would only believe and confess that Jesus is the Son of God, and that he rose from the dead, and that He is Lord. Then he would be able to believe Jesus' message of repentance. How can he repent if he is not a born again believer, am I wrong about him?
While we have Peter's words to Cornelius and his household recorded for us, you need to keep in mind that nothing states that we have the complete sermon. There is indication that repentance was discussed. In hearing about what happened in Caesarea, the Christians in Jerusalem made this comment, "When they heard these things they became silent; and they glorified God, saying, "Then God has also granted to the Gentiles repentance to life."" (Acts 11:18). Whether directly mentioned or not, the disciples in Jerusalem knew that repentance was involved in the Gentiles' salvation.
Is repentance important? Jesus said twice, "I tell you, no; but unless you repent you will all likewise perish" (Luke 13:3, 5). This should settle the matter. Without repentance, you cannot be saved -- period. Paul told the Athenians, "Truly, these times of ignorance God overlooked, but now commands all men everywhere to repent" (Acts 17:30). Can you be saved by ignoring a command of God?
You are correct that there would be no motivation to repentance without faith in God and His Word. "If you love Me, keep My commandments" (John 14:15). But then again, a person cannot have faith until he learns of God. "So then faith comes by hearing, and hearing by the word of God" (Romans 10:17). Hence, faith is not independent. You must hear first before you can believe. Does that mean that faith is not necessary because hearing preceded faith? I think in this point you and I both agree; faith remains necessary. Yet, Peter said, "Since you have purified your souls in obeying the truth through the Spirit in sincere love of the brethren, love one another fervently with a pure heart, having been born again, not of corruptible seed but incorruptible, through the word of God which lives and abides forever" (I Peter 1:21-22). Peter said you are born again through the word of God. Where is the mention of faith? Does this mean I can be saved only by hearing the word of God? Again, you and I would both agree that it is obviously not the case. Therefore, just because faith precedes other things connected with salvation, it does not mean those other things are unnecessary for salvation.
Even in your own note, you slipped and added more to salvation than just faith. You said, "I believe that my father would be born again if he would only believe and confess that Jesus is the Son of God, and that he rose from the dead, and that He is Lord." Even though you did not mention confessing Jesus in your own life, you state that it would be necessary for your father. Paul stated, "But what does it say? "The word is near you, in your mouth and in your heart" (that is, the word of faith which we preach): that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved. For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation" (Romans 10:8-10). Can you be saved without confessing Christ? Paul says "No." But would a person confess without belief? There would be no motivation to do so. Belief may precede confession, but both belief and confession are necessary for salvation.
In proving that faith alone is insufficient to save a person, James pointed out that demons believe and yet are not saved. "You believe that there is one God. You do well. Even the demons believe--and tremble!" (James 2:19). There is an example found in the gospels. "Now there was a man in their synagogue with an unclean spirit. And he cried out, saying, "Let us alone! What have we to do with You, Jesus of Nazareth? Did You come to destroy us? I know who You are--the Holy One of God!"" (Mark 1:23-24). No one would claim that the demon was saved simply because he confessed that Jesus was the Holy One of God. Demons are not the only example. Among the Jews we learn, "Nevertheless even among the rulers many believed in Him, but because of the Pharisees they did not confess Him, lest they should be put out of the synagogue; for they loved the praise of men more than the praise of God" (John 12:42-43). No matter how you slice it, these men believed because God said they did, yet that belief was insufficient.
You also asked if one born again can be saved if he does not continue to obey the Lord God. Paul tells us that there are two classes of people on whom Jesus will take vengeance when he returns. "In flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ" (II Thessalonians 2:8). Those who do not know God and those who do not obey God will face God's wrath. You see, Jesus is the Savior of the obedient. "And having been perfected, He became the author of eternal salvation to all who obey Him" (Hebrews 5:9). And God is not expecting temporary obedience. "Be faithful until death, and I will give you the crown of life" (Revelation 2:10).
Rather than focusing on doing only part of God's will, look at all that the Scriptures teach about salvation. See the Salvation Table to get a better idea how many ideas inter-work to accomplish the same goals. See the Conversion Table to see how the many examples of people who were saved, including Cornelius, did the various things God commanded of them. For a list of verses connected to the idea of being born again, see the topical index "Born Again."