But truly I am full of power by the spirit of the LORD, and of judgment, and of might, to declare unto Jacob his transgression, and to Israel his sin.
But truly I - in contrast to the false prophets (Micah 3:5; Micah 3:7).
Am full of power by the Spirit of the Lord - that which "the Spirit of Yahweh" imparts for the discharge of the prophetic function (Luke 1:17; Luke 24:49; Acts 1:8, "Ye shall receive power afar that the Holy Spirit is come upon you").
And of judgment - a sense of justice (Maurer); as opposed to the false prophets' speaking to please men, not from a regard to truth. Or, judgment to discern between graver and lighter offences, and to denounce punishments accordingly (Grotius).
And of might - moral intrepidity in speaking the truth at all costs (2 Timothy 1:7).
To declare unto Jacob his transgression, and to Israel his sin - (Isaiah 58:1). Not to flatter the sinner, as the false prophets do, with promises of peace.