Perek 25 is the first perek in Yirmiyahu which opens with the date on which the prophecy was said. During the prophecy, Yirmiyahu summarizes twenty-three years during which he tried in vain to cause the nation to repent and change their ways. Because the people refused to listen to the prophecies they will be punished by the king of Babylonia, who will destroy the land and enslave the people. In the second half of the perek (15-38) the calamity spreads past the borders of Israel. The prophecy describe the "wine cup of fury" which God will give to the nations to bring them to their destruction. It seems that the prophetic vision in these pesukim symbolizes the domination of the Babylonian empire over the nations and kingdoms mentioned in the prophecy.
Perek 26 goes back to deal with Yirmiyahu's prophecy about the Temple, a prophecy which first appeared in perek 7, this time from a different angle. While perek 7 focused on the content of the prophecy, our perek focuses on the story of Yirmiyahu being put on trial for the prophecy of the destruction of the Temple (described in brief in pesukim 1-6), and on the rescue of Yirmiyahu from death as a result of his pronouncements. The Priests make a serious accusation against Yirmiyahu, but his response does not directly answer their accusation, and so he brings a second explanation to prove his innocence. The story presents to us the nation's distorted perception of holiness in relation to Jerusalem.
Courtesy of Matan Al HaPerek, Directed by Dr. Navah Cohen