What exactly did Jesus command His disciples about going to Gentiles and Samaritans?

Jesus commanded the twelve, at the beginning of His earthly ministry, not to go into the way of the Gentiles and not to enter any city of the Samaritans. This was not a suggestion but a command from the Lord of Glory, carrying highest authority.

Les explains that in Matthew 10:5, after calling the twelve in the first four verses, Jesus sent them forth at the beginning of His earthly ministry. He did not merely suggest this; He commanded them, saying, “Go not into the way of the Gentiles, and in any city of the Samaritans enter ye not.” Since He is the Lord of Glory, His command carries the highest authority. The Samaritans at that time were half-breed Jews who had lost their pure character as Jews and were looked down upon and detested by the pure Jew. Les notes that Jesus would later in His ministry still go to the city of Samaria.

Matthew 10:5

These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not:

What exactly did Jesus command the twelve in Matthew 10 about Gentiles and Samaritans?

At the onset of His earthly ministry, Jesus commanded the twelve not to go into the way of the Gentiles and not to enter any city of the Samaritans. Instead, He directed them to go rather to the lost sheep of the house of Israel.