Then Jonathan said to David, To morrow is the new moon: and thou shalt be missed, because thy seat will be empty.
Tomorrow is the new moon, х chodesh (H2320)]. The first day of the lunar month was held as a festival among the Hebrews.
Related Commentaries of 1 Samuel 20:18
1 Samuel 20:18
18 Then Jonathan said to David, To morrow is the new moon: and thou shalt be missed, because thy seat will be empty.f