18 And Jesus came and said to them, "All authority in heaven and on earth has been given to me. 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age." —Matthew 28:18-20 ESV
Referring to the above verses of Matthew 28, the following narrative of the entire chapter provides the context with and to which it refers:
The Report of the Church
16 Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them.
This mountain is reminiscent of the other sites of revelation in the Gospel (Sermon on the Mount 5:1; The Transfiguration 17:1). All our primary corroboration indicates the Christian missionary momentum, suggesting that it arose from Jesus, as heterogeneous Gospel accounts affirm. Mary Magdalene offered a legitimate explanation (The Resurrection 28:1-10) and the guards one fabricated for money (11-15). The final paragraph commands that we, like Mary, must give an honest report and resist the temptation of money and safety that the guards fell prey to.
The story teaches us about belief and skepticism. Verse 9 suggests that those who clasped his feet and worshiped him recognize him for who he is--"God with them" (1:23; Isaiah 7:14). But others are skeptical (v. 17) or even too amazed to believe (as in Luke 24:40). As is true with Mark (Mark 16:8) that disciples often are foolishly unbelieving:
30 If that is how God clothes the grass of the field, which is here today and tomorrow is thrown into the fire, will he not much more clothe you, O you of little faith? —Matt 6:30