When He was on Earth in the flesh He focused mainly on Hebrews/Jews, but right before His ascension He told them to teach the Gentiles what He had taught them.
Disciples sent out before Sacrifice/Resurrection:
Matthew 10:5, "יהושע sent these twelve out, having commanded them, saying, “Do not go into the way of the nations, and do not enter a city of the Shomeronim,"6, "but rather go to the lost sheep of the house of Yisra’ĕl."7, "“And as you go, proclaim, saying, ‘The reign of the heavens has drawn near.’"8, "“Heal the sick, cleanse the lepers, raise the dead, cast out demons. You have received without paying, give without being paid."9, "“Do not acquire gold or silver or copper for your money-belts,"10, "or a bag for the journey, or two undergarments, or sandals, or staffs, for the worker is worthy of his food."11, "“And into whatever city or village you enter, ask who is worthy in it, and stay there until you leave."12, "“And as you enter into a house, greet it."13, "“And if the house is worthy, let your peace come upon it. But if it is not worthy, let your peace return to you."14, "“And whoever does not receive you nor hear your words, when you leave that house or city, shake off the dust from your feet."
Disciples sent out after Sacrifice/Resurrection:
Matthew 28:18-20, “And יהושע came up and spoke to them, saying, “All authority has been given to Me in heaven and on earth. Therefore, go and make disciples of all the nations, immersing them in the Name of the Father and of the Son and of the Set-apart Spirit, teaching them to guard all that I have commanded you. And see, I am with you always, until the end of the age.” Awmĕin."
“nations” is word #G1484 ἔθνος ethnos (eth'-nos) n., 1. a race (as of the same habit), i.e. a tribe., 2. (specially) a foreign (non-Jewish) one, Gentiles., 3. (usually, by implication) pagan., [probably from G1486], KJV: Gentile, heathen, nation, people , Root(s): G1486