The indignation is a 75 day period that will occur at the end of Daniel's seventieth week. It is a technical term in the prophetic scriptures that refers to a series of judgments. A number of references will make clear that this period is when God will vent His indignation on the earth for, above all, rejecting His Son.
"Come, my people, enter thou into thy chambers, and shut thy doors about thee: hide thyself as it were for a little moment, until the indignation be overpast." Isa. 26:20
"And he said, Behold, I will make thee know what shall be in the last end of the indignation: for at the time appointed the end shall be." Dan. 8:19
"And the king shall do according to his will; and he shall exalt himself, and magnify himself above every god, and shall speak marvellous things against the God of gods, and shall prosper till the indignation be accomplished: for that that is determined shall be done." Dan. 11:36
Two attacks of the Assyrian. Generally speaking, the indignation stretches across the two attacks of the Assyrian. A verse to show that is Isa. 10:5. From Daniel and Revelation we can conclude that the first attack of the Assyrian (the King of the North) will occur at 1260 days, and the second attack (Gog and Magog) will occur at 1335 days measured from the middle of Daniel's 70th week. The space of time covered by the indignation therefore is 75 days.
"O Assyrian, the rod of mine anger, and the staff in their hand is mine indignation. ... For yet a very little while, and the indignation shall cease, and mine anger in their destruction." Isa. 10:5, 25
Seven Battles of the Indignation. Students of prophecy have used different schemes to describe the events of this period, but my favorite approach is to view the indignation as a series of seven battles (credit to Bruce Anstey). Over the period of 75 days, there will be more bloodshed than ever in the history of the world.