No! You are wrong. James 5:18, is for all believers, not just the Jews. I reiterate, James says, "my brothers," i.e. other believers in Christ. With your interpretation of this, you would be saying the Jew and Gentile have two different plans of salvation. James is speaking to both Jew and Gentile Christians and therefore, the scripture is to be applied to all. James is certainly not speaking about wandering Jews returning to the law of Moses, but to Jews and Gentiles who wander away from faith.
Let me address this particular misconception, which was part of the longer post you made to me previously.
Jews and Gentiles have the same plan of salvation now, which is 1 Cor 15:1-4
But before the dispensation of grace that was first revealed to Paul (Ephesians 3:9),
the salvation plan for Israel as a nation was different.
To be saved before that, the nation must obey the covenant that God has set for them, which is stated in a few places, the clearest for our purpose here is Exodus 19
5 Now therefore,
if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine:
6 And y
e shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel.
How does Israel, as a nation, keep God's covenant that he made with them after Mount Sinai? That is thru the Law of Moses. God gave them many commandments to keep, and at the same time, provided a system of animal sacrifices for them when they fail to keep it perfectly.
After Jesus arrive in the flesh, there is a new commandment for all Israel to follow, which is inline with what we are discussing about in Mark 16:16.
They are to repent from disobeying God previously when they stoned the OT prophets that God sent to them previously to urge them to go back to the Law of Moses, and to believe that Jesus is their promised Son of God.
In a few places we see this, the clearest of course is from Stephen in Acts 7:52
52
Which of the prophets have not your fathers persecuted? and they have slain them which shewed before of the coming of the Just One; of whom ye have been now the betrayers and murderers:
Jesus also spoke about this in the parable of the vineyard owner in Mark 12:1-5.
If Israel is willing to do this, they will be reborn or born again. What is the next task for them to obey in order to keep the covenant? All Jews must be water baptized, this was not a requirement before Jesus came in the flesh
Under the gospel of the kingdom preached to Israel only, water baptism is a requirement for salvation. Israel as a nation was supposed to accept Jesus as their Messiah and be ushered into their promised kingdom where Jesus will rule over them from David's throne in Jerusalem.
Then Israel will become a kingdom of priest, in order to be a priest, every Jew MUST be baptized (Exodus 19:4-6)
Once that happen, then every Jew will be responsible to spread the gospel to every Gentile nation under the Earth. There are a number of OT passages that talk about this prophetic timetable, the most beautiful to me is found in Zechariah 8
3 Thus saith the Lord; I am returned unto Zion, and will dwell in the midst of Jerusalem: and Jerusalem shall be called a city of truth; and the mountain of the Lord of hosts the holy mountain.
7 Thus saith the Lord of hosts; Behold, I will save my people from the east country, and from the west country;
8 And I will bring them, and they shall dwell in the midst of Jerusalem: and they shall be my people, and I will be their God, in truth and in righteousness.
20 Thus saith the Lord of hosts; It shall yet come to pass, that there shall come people, and the inhabitants of many cities:
21 And the inhabitants of one city shall go to another, saying, Let us go speedily to pray before the Lord, and to seek the Lord of hosts: I will go also.
22 Yea, many people and strong nations shall come to seek the Lord of hosts in Jerusalem, and to pray before the Lord.
23 Thus saith the Lord of hosts; In those days it shall come to pass, that ten men shall take hold out of all languages of the nations, even shall take hold of the skirt of him that is a Jew, saying, We will go with you: for we have heard that God is with you.
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So once you understand this, you can understand why I believe Mark 16:16 is not directed to us gentiles, which address your point to me in that longer post.
We gentiles were not included in that covenant when Jesus was first sent in the flesh (Matthew 15:24, Matthew 10:5, Ephesians 2:11-12, and Romans 15:8).
If we wanted to be saved during that time period, which Paul described as time past (Ephesians 2:11-12), we had to join the nation Israel, which requires physical circumcision for males and obeying the Law of Moses. We could not approach God as gentiles during time past, without going thru the nation Israel, which was what the Roman Centurion did, as you mentioned in that post to me.
It was only after Israel the nation rejected the messiah for the final time by stoning Stephen, God announced to the whole world the good news thru the apostle Paul that, all of us, gentiles or Jews can be saved thru believing in Jesus death burial and resurrection (Romans 11:11, 1 cor 15:1-4).
Under this gospel of grace first revealed to Paul, Israel as a nation has fallen, and now both Jews and gentile have the same plan for salvation, which is salvation by faith apart from works (Romans 4:5)