Verses 19, 20 constitute the great charter of the Christian church. In the word “ye” Christ included all believers to the very end of time (see DA 822; cf. 819). As disciples, the Eleven had been learners in the school of Christ; now, as apostles, they were sent forth to teach others (see on Mark 3:14). For further comment on the responsibility of believers in Christ to share their faith see on Matt. 5:13-16; Luke 24:48.
Therefore.
That is, in view of the “power” referred to in v. 18.
Teach all nations.
Literally, “make disciples of all nations,” including both Jews and Gentiles in every nation (cf. Rom. 1:16; 2:10). Compare this with the great promise that the gospel of the kingdom would be “preached in all the world for a witness unto all nations” (see on Matt. 24:14). This commission is sometimes referred to as the “charter of foreign missions.” Christianity was the first religion to assume a truly international character. Pagan religions were largely devoid of missionary zeal and activity. They were primarily national in character and did not set out to make converts of other national groups. The gospel commission effectively eliminates national boundaries, and men of all nations find themselves members of one great brotherhood in which “there is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female,” for all are “one in Christ Jesus” (Gal. 3:28; cf. Col. 3:11). Christianity effectively destroys all barriers of race, nationality, society, economics, and social custom. Christianity depends for success on its disentanglement from all national peculiarities, forms of government, social institutions, and everything of a purely local character.
Or, “Holy Spirit.” See on ch. 1:18. For the office and work of the Holy Spirit see John 14:16-18; John 16:7-14. The nature of the Holy Spirit is a divine mystery, one on which Inspiration has not seen wise to speak. On this subject speculation is futile.