“Jesus states, ‘All authority on heaven and earth have been given to me” (v. 18). Reference to being given authority in heaven and on earth recalls the Son of Man in Dan 7:13-14, who in heaven was given ‘authority’ and authority later claimed ‘on earth’ (cf. Matt 9:6, ‘the Son of Man has authority on earth’; Matt 21:23, ‘By what authority are you doing these things, and who gave you this authority?’; Matt 7:29, ‘he taught them as one having authority’). The heavenly authority of Jesus is such that he even commands angels (cf. Matt 16:27, ‘the Son of man is to come with his angels in the glory of the Father’; 24:31; 25:31, ‘the Son of Man comes in his glory, and all the angels with him’).
“The ‘authority’ here in Matt 28:18 probably alludes to the authority granted to the ‘Son of Man’ in Dan 7:14: ‘And royal authority was given to him…his authority is an everlasting authority’ (NETS). The risen Jesus can speak of his authority ‘in heaven’ because that is where the authority was granted –in heaven and in the very presence of God. The claim to have authority ‘on earth’ recalls Jesus’ earlier demonstration that he indeed does possess this authority, which he announced on the occasion of healing the paralyzed man (cf. Matt 9:6, ‘the Son of Man has authority on earth’).”
Quite the imagery: the Son of Man figure receives authority from the Ancient of Days and authoritatively commissions his disciples to make disciples of all the nations. In Daniel 7 the Son of Man figure is given the Kingdoms. Jesus has been given the Kingdoms, so he instructs his disciples to inform the Kingdoms that there has been a change. This seems to be underpinned by Psalm 2 as well where God choses his King and the nations prepare their defense against him, yet in this Gospel the King expects his disciples to find loyalist among the nations who will declare their allegiance to the King.