A mistake that is made in learning what we must do to be saved is by consulting only the books written to the saved without looking at what else is said in Scripture.
For example, many will quote the book to the Roman Christians; (Rom 10:9) without considering what Paul taught the Romans when he dwelt there for two whole years. [Acts 16:30]
They will quote the book written to the Ephesian Christians; (Eph 2:8-9) without considering what Paul taught the Ephesians [Acts 19:1-5].
These two examples show us why we must look into the book of Acts to see what lost people did. Those who heard the gospel and either obeyed it or rejected it. This is why it could be called the book of Conversions.
Let’s examine just a few of the conversions in this book to see how they responded to the preaching of the Gospel as commanded by Christ Jesus. [Mat 28:18-20]
Jews at PENTECOST [2:14-47] This represents the first gospel sermon after the DBR of Christ. The beginning of the church that Jesus promised to build [Mat 16:18] and the first example of those being saved. “Be saved from this perverse generation.” What happened? They HEARD the gospel [22-36]. They believed . It must be inferred that they CONFESSED Jesus as the Christ the Son of God [Mt 10:32]. They were told to ‘REPENT & be baptized’ . They were BAPTIZED into Christ  and 3,000 were added to the church. Then we see them ‘CONTINUING steadfastly in the Apostles Doctrine, which is from Christ [42; cr. John 14:26; 15:26; 16:13; 1Cor 14:37].
THE ETHIOPIAN EUNUCH [8:26-39] This man is reading from Isaiah and struggling with its meaning. Philip approaches him and is invited by the Eunuch to explain the passage. We then are told, “Then Philip opened his mouth, and beginning at this Scripture, preached Jesus to him.” What Happened? He HEARD the gospel of Jesus . He BELIEVED [36-37] It is inferred that he REPENTED [Luke 13:3; Acts 17:30]. He CONFESSES that Jesus is the Christ . He is BAPTIZED with water, by immersion, into Christ [38-39 cr. Rom 6:3-4; Gal 3:27]. He went away REJOICING .
The Apostle PAUL (Saul of Tarsus) [9:1-18; 22:6-16; 26:12-19]. While on his way to persecute the church of Christ, Saul saw Jesus risen from the dead. He HEARD & BELIEVED [9:5-6]. He was REPENTANT [9-11]. He CONFESSED [5-6]. He was BAPTIZED . When retelling of this event, he states that baptism was the moment his sins were washed away [22:16].
CORNELIUS [10:1-11:18] This story tells of the first Gentile conversion. We must read chapters 10 & 11 to get the full picture. They were told to HEAR and they HEARD [6, 22, 33-43; 11:14]. It is inferred that they REPENTED & CONFESSED [Luke 13:3; Act 17:30; Mat 10:32]. They were BAPTIZED in water . They received remission of sins .
Chapter 11:1-18 contains the retelling of this event by Peter to those of the circumcision who contended with him about being with gentiles. This retelling is necessary to show that God had made the same gospel plan of salvation available to every nation [Mat 28:18-20]. Up to this point, the preaching had been only to the Jews. “For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek.” [Rom 1:16] The “Baptism of the Holy Spirit” only occurred twice, here and at Pentecost. It was done to show God’s approval at the beginning.
As you can see, the book of Acts shows people obeying the Gospel. The same method can be applied to…
THE JAILER [16:25-34]
THE CORINTHIANS. [18:8]
THE EPHESIANS [19:1-5]
The same Gospel requires all after Pentecost to HEAR, BELIEVE, REPENT, CONFESS, be BAPTIZED in water & have FAITHFULNESS. God shows no partiality, no bigotry. The Gospel is for all and all must obey the Gospel in the same way. God is no respecter of persons.
“He became the author of eternal salvation to all who obey Him,” [Hebrews 5:9; cr 2Thess 1:8-9; 1Cor 15:1-4] –Spencer