John Gill Commentary 1 Kings 16:15

"In the twenty and seventh year of Asa king of Judah did Zimri reign seven days in Tirzah. Now the people were encamped against Gibbethon, which belonged to the Philistines." — 1 Kings 16:15 (ASV)

In the twenty and seventh year of Asa king of Judah Zimri
reigned seven days in Tirzah ,
&c] Until the army under Omri came and took the palace, and destroyed him:

and the people were encamped against Gibbethon, which belongs to the
Philistines ;
it was besieged in Nadab's time, but upon his death, by Baasha, the siege was raised; or however, if then taken, it was recovered by the Philistines, and now besieged again by the Israelites, see (1 Kings 15:27) .