18 Then Jonathan said to him, "Tomorrow is the new moon: and you will be missed, because your seat will be empty.
*Minor differences ignored. Grouped by changes, with first version listed as example.
Then Jonathan said to David, tomorrow is the new moon,.... The first day of the month, as David had before observed, 1-Samuel 20:5,
and thou shalt be missed, because thy seat will be empty; or be inquired after, because not in his usual place at mealtime.
*More commentary available at chapter level.