"Go and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit. Teach these new disciples to obey all the commands I have given you. And be sure of this: I am with you always, even to the end of the age."

(Matthew 28.19-20 NLT)

Baptism was a common way in that period for gentiles to proclaim conversion into the Jewish faith. (Just like now it proclaims conversion into the Christian faith.)

And on the Jewish faith that Jesus built his teachings on: earlier in the book, Jesus said something about the "greatest commandment".

“‘You must love the Lord your God with all your heart, all your soul, and all your mind.’ This is the first and greatest commandment. A second is equally important: ‘Love your neighbour as yourself.’”

(Matthew 22.37-39 NLT)

If I may reinterpret Jesus' last instruction in the book of Matthew, I would say this. Go and make disciples to obey Jesus' teachings on the "greatest commandment".