I Samuel 12:2

וְעַתָּה הִנֵּה הַמֶּלֶךְ מִתְהַלֵּךְ לִפְנֵיכֶם וַאֲנִי זָקַנְתִּי וָשַׂבְתִּי וּבָנַי הִנָּם אִתְּכֶם וַאֲנִי הִתְהַלַּכְתִּי לִפְנֵיכֶם מִנְּעֻרַי עַד הַיּוֹם הַזֶּה

Now, behold! The king walks before you. I am old and gray and, behold, my sons are with you. I have walked before you from my youth until this day.

The prophet Shmuel chastised the Jews for demanding a king in order to be like the other nations. The Metzudas David explains that before doing so, he pointed out (a) that he was already old and (b) that his own sons were with the people in their support of the king. Therefore, it should be obvious that he had no interest in the throne for himself or his heirs, and his criticisms were without any ulterior motive.