“burdensome message.” The word of the Lord can be a burden to the prophet, and then, when it is spoken, can be a burden to the people. The Hebrew word means “burden,” but some scholars say it refers to a message, an oracle. In this context, as in many others in the Old Testament, it was the word of Yahweh that was the burden because of its weight and severity. The NET translation, “burdensome message,” seems to catch the sense well. [For more information on “burden,” see commentary on Malachi 1:1].
“You are the burden.” This translation follows the Septuagint and Latin (cp. ESV, NAB, NET, NLT, NRSV, RSV). The Hebrew reads “What burden” and is much less clear in this context and does not connect the two final sentences in the verse. The ungodly priests and false prophets were being a burden to God, so He decided to cast them away and not carry them anymore.