In 2 Samuel 16, when David flees Jerusalem after Avshalom's conspiracy, Ziba the slave comes to David with provisions, and claims Mephibosheth that has broken faith with David to join Avshalom. David responds by giving all that belonged to Mephibosheth to his slave Tziva instead. Finally, in 2 Samuel 19,28 when David returns to Jerusalem, Mephibosheth tells David that Tziva had been lying וירגל בעבדך אל אדני (. David responds by saying "You and Tziva shall divide the land."
the Gemara Yuma 22b says:
לרב נמי דאמר קבל דוד לשון הרע הא איפרעו מיניה דאמר רב יהודה אמר רב בשעה שאמר לו דוד למפיבושת (שמואל ב יט, ל) אמרתי אתה וציבא תחלקו את השדה יצאה בת קול ואמרה לו רחבעם וירבעם יחלקו את המלכות
When tziva the slave said to David Lashon Hara about Mefiboshes and David accepted and said they should divide Mefiboshes' estate, as a punishment heavenly voice came out and said "Rechavam and Yeravam should divide the kingdom" (that was supposed to be solely under Monarchy of Davids lineage Rechavam).
A slave is obligated tokeep Mitvos Lo taase including not saying Lashon Hara just like a woman (Yevamos 48a), and David was obligated not to listen to Lashon Hara.