Nutshell for "Machar Chodesh" Haftorah
Since this Shabbat is the day before Rosh Chodesh, we read a special haftorah that begins with the words "machar chodesh" — "[And Jonathan told David,] 'Tomorrow is the new moon…’”
I Samuel 20:18-42.
David, King Saul's son-in-law, fears that his father-in-law views him as competition for his throne, and wishes to have him killed. David enlists his dear friend Jonathan, Saul's son, to ascertain whether indeed Saul has such evil designs. Together they devise a plan, according to which David will be absent from the monthly new moon feast hosted by Saul. At this feast, Jonathan will discover Saul's true intentions with regards to David. Jonathan and David will then rendezvous at a predetermined meeting point where Jonathan will convey to David whether he should return to the royal household or flee.
When everyone is seated at the royal feast, the king notices David's absence and asks Jonathan for his whereabouts. When told that he has gone to Bethlehem to be with his family, the king becomes furious, telling Jonathan to fetch David as he is condemned to death. "And Jonathan knew that it had been decided upon by his father to put David to death."
Jonathan leaves the royal table in anger. The next morning he travels to David's hiding place and the two separate amidst an emotional farewell, promising each other eternal devotion and friendship.
The above haftorah is read since this Shabbat is the day before Rosh Chodesh. In other years, we would read the following text:
RE: Machar Chodesh - why? The Chassidic masters see many mystical references in this haftorah to the chain of events leading to the coming of Moshiach, and the spiritual events which it holds. It seems to me that the day before the moon is renewed symbolized the time right before the coming of Moshiach—the time when all of these events are played out.
Others point out that one important reason for reading this haftorah is that we see here an account of Rosh Chodesh was celebrated as a day of feasting and celebration by Jewish people as far back as the days of Saul and David.