"...he brought them out and said, 'Sirs, what must I do to be saved?' And they said, 'Believe in the Lord Jesus, and you will be saved, you and your household'" (Acts 16:30-31).
"'...now why do you wait? Rise and be baptized and wash away your sins, calling on his name’" (Acts 22:26).
"Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, 'Brothers, what shall we do?' And Peter said to them, 'Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit'" (Acts 2:37-38).
"'...it shall be that everyone who calls on the name of the Lord will be saved'" (Acts 2:21).
When people desired salvation in Christ, why were they given different answers?
One is told to believe, others are to repent, still another was told to arise and be baptized...how are we to make sense of this?
If someone were to ask you, "How far is it to Mt. Rushmore?" Your answer would depend upon the location of the person asking. For someone in central Texas, it's an eighteen hour drive, but for someone in Keystone, South Dakota it's eleven minutes away. Very different answers, of course, but both are right. Both are part of the same Truth.
David said, "The sum of your word is truth, and every one of your righteous rules endures forever" (Ps. 119:160).
I appreciate that principle--"the sum of Your Word." We take what God says, we add it up, and that is Truth. We don't take one part and run with it, and assume we have all the information. Be concerned with the "whole counsel of God" (Acts 20:27).
Why do the answers differ for people desiring to be saved?
Because they were asked by different people in different circumstances.
An honest examination of each passage will reveal the same conditions for salvation were taught to all, and combining the teachings of these texts shows us how to find salvation in Christ.
If we take the reply given to the jailer, "Believe on the Lord Jesus and you will be saved..." as exclusive, we're going to conclude wrongly that belief is the sole condition for salvation in Christ. "You believe that God is one. You do well; the demons also believe, and shudder" (Jas. 2:19).
If we take the instructions given to the men on Pentecost, "Repent and be baptized..." as exclusive, then we will wrongly conclude that belief is not required at all. We could easily commit the same fallacy with the instructions given to Paul by Ananias (wherein no mention of belief or repentance appears): "Arise an be baptized...".
When the jailer asked his question, he had no previous knowledge of Jesus Christ, thus could not believe on Him, but as he is taught by Paul and Silas, he believes, he repents, and is baptized into Christ:
...they spoke the word of God to him together with all who were in his house.
And he took them that very hour of the night and washed their wounds, and
immediately he was baptized, he and all his household. (Acts 16:32-33)
Only then does the Holy Spirit describe the jailer as "...overjoyed since he had become a believer..." (Acts 16:34).
The same is true of the men on Pentecost who had been listening to Peter preach the Truth about Jesus. Having believed, they asked, "What shall we do?" The instructions were "...repent and be baptized for the forgiveness of sins" (Acts 2:37-38).
Likewise, Saul of Tarsus having been confronted by Jesus on the road to Damascus eagerly believed, and was repentantly praying for three days without eating or drinking anything (Acts 9:9-11), thus he was told, "Arise and be baptized, washing away your sins, calling on the Name of the Lord..." (Acts 22:16).
Different replies, but all are part of the same great Truth. These individuals were in different circumstances, and were told specifically what they needed to hear (a needed lesson for teachers).
So the question, "What must I do?" must be answered in light of your circumstances. The Gospel is for all, and Jesus is the source of salvation to all who obey Him (Heb. 5:9). What must you do to obey Him? He Himself said, "He who believes and baptized will be saved, he who does not believe will be condemned" (Mk. 16:16). Do you believe Jesus is the Son of God? If so, have you repented of your sins? Have you been baptized for the forgiveness of your sins? (1 Pet. 3:21)