1 Corinthians 10:1-4 (KJV)
1 Moreover, brethren, I would not that ye should be ignorant, how that all our fathers were under the cloud, and all passed through the sea;
2 And were all baptized unto Moses in the cloud and in the sea;
3 And did all eat the same spiritual meat;
4 And did all drink the same spiritual drink: for they drank of that spiritual Rock that followed them: and that Rock was Christ.
The Israelites were baptized unto Moses. Yet we as New Testament believers are baptized unto Christ.
Romans 6:3-4 (ESV)
3 Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death?
4 We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life.
Galatians 3:27-29 (ESV)
27 For as many of you as were baptized into Christ have put on Christ.
28 There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female, for you are all one in Christ Jesus.
29 And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise.
Here is a quote from John MacArthur on this subject:
Paul was recounting the children of Israel in the wilderness “Baptized into Moses” means the children of Israel came under the authority of Moses. To be baptized into Moses was to be involved in all that God was doing in the life of Moses. Moses was the channel through which God spoke to the children of Israel. He was their anchor to God. In a deeper and more profound sense, believers are baptized into Jesus Christ.
Galatians 2:16, 19–Paul said, “A man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law; for by the works of the law shall no flesh be justified…. For I, through the law, am dead to the law, that I might live unto God.“
The Judaizers–Jews who believed circumcision was essential for salvation–went into the Galatian region and found people teaching that you could enter into God’s Kingdom by God’s grace alone. They countered that you first must be circumcised, followed by diligent obedience to the law of Moses, and only then could you come into God’s Kingdom. This is not unlike today. Most people think you must follow all sorts of rules to be spiritual. They think by enforcing particular rules, they can fit people into a certain mold of spirituality.
Who’s authority are you under?