The command given by the Lord is likely the same as the commandment which we read about in 2 Peter 2:21. In that instance it probably has to do with the substance of the initial teaching that new converts receive—basic teaching of Christ.1 Alternatively it could refer to ethical teaching or teaching regarding the return of Christ.2 Either way, the teaching conveyed by the apostles represented the words of Jesus Christ. They taught not on their own authority but transmitted his words.3
2 that you should remember the predictions of the holy prophets and the commandment of the Lord and Savior through your apostles,