"And he said unto them, Go ye into all the world, and preach the gospel to every creature." (Mark 16:15)
The so-called "great commission" of the Lord to His disciples is found in somewhat different form in each of the four gospels and in still another form in the first chapter of Acts. To get the full message of the commission, all five must be analyzed and organized together.
The most familiar statement is in Mark 16:15 above. This was in the upper room and must have followed the words recorded by John: "Peace be unto you: as my Father hath sent me, even so send I you" (John 20:21).
The commission was then further defined as recorded in Luke 24:47-48: "that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem. And ye are witnesses of these things."
Still later, on a mountain in Galilee, He told the disciples (literally): "Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you" (Matthew 28:19-20). Not only were they to preach the saving gospel, implemented by true repentance unto remission of sins, based on His death, burial, and resurrection (Luke 24:46), but then to "disciple" them, baptize them, and indoctrinate them in all His teachings.
Finally, just before His ascension, He summarized the commission once again: "ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth" (Acts 1:8). Above all, we are to go and to witness to all people in all places, as God enables. HMM