The nation gathers at Gilgal for a second coronation of King Saul, the first one having lacked a convincing consensus. They offer sacrifices and rejoice together. The prophet Samuel then delivers a talk: he asks the people to testify that he never committed crimes against the people, and they confirm. He discusses how G‑d saved and aided them every step of the way and chastises them for wanting a flesh and blood king. He assures them that G‑d will be with them if they follow in His ways, and of the consequences they will face if they do not follow G‑d’s word.
To underscore the seriousness of his words, Samuel asks G‑d to send a thunderstorm, although it was not the rainy season. The Jewish people got the message and asked Samuel to intercede on their behalf and to have the thunderstorm cease. The haftarah ends with a reassurance: “For G-d will not forsake His people for His great name’s sake; for G-d has sworn to make you a people for Himself.”
Haftarah summary courtesy of Chabad.org