16 Then the eleven disciples left for Galilee, going to the mountain where Jesus had told them to go. 17 When they saw him, they worshiped him—but some of them doubted!
It is in this context that Jesus first assures His disciples and then commissions them to the good work of spreading the good news and making disciples who will make more disciples.
Jesus draws near that mixed group of worshipping/doubting disciples and assures them that He has ALL authority in Heaven and earth, so in other words, He has all authority everywhere that authority could be had.
He then says, "therefore."
Since that is true, go and tell the world that Jesus is God and immerse them into this God and teach them everything He commanded and help them to obey those commands as they seek to obey and trust Him alone.