Jamieson, Fausset and Brown on Zephaniah 1:7

7. Hold thy peace at the presence of the Lord--(Ha 2:20). Let the earth be silent at His approach [Maurer]. Or, "Thou whosoever hast been wont to speak against God, as if He had no care about earthly affairs, cease thy murmurs and self-justifications; submit thyself to God, and repent in time" [Calvin].

Lord ... prepared a sacrifice--namely, a slaughter of the guilty Jews, the victims due to His justice (Is 34:6; Jr 46:10; Eze 39:17).

bid his guests--literally, "sanctified His called ones" (compare Is 13:3). It enhances the bitterness of the judgment that the heathen Chaldeans should be sanctified, or consecrated as it were, by God as His priests, and be called to eat the flesh of the elect people; as on feast days the priests used to feast among themselves on the remains of the sacrifices [Calvin]. English Version takes it not of the priests, but the guests bidden, who also had to "sanctify" or purify themselves before coming to the sacrificial feast (1Sa 9:13, 22; 16:5). Nebuchadnezzar was bidden to come to take vengeance on guilty Jerusalem (Jr 25:9).