The haftarah of the seventh day of Pesach is the song of David HaMelech to parallel Az Yashir/Shirat HaYam in the Torah Reading. The last verse of the haftarah (Shmuel II 22:51) reads:
“מגדול ישועות מלכו ועושה חסד למשיחו לדוד ולזרעו עד עולם”
This pasuk is repeated almost word-for-word in Tehillim (ch. 18) where the first word is spelled without a vav (magdil):
“מגדל ישועות מלכו ועושה חסד למשיחו לדוד ולזרעו עד עולם”
in Shmuel it is spelled with a vav (migdol). During the week we use the verse from Tehillim and on Shabbos we use the verse from Shmuel. What does the version in Shmuel have to do with Shabbos and Yom Tov?
The Avudraham, Pri Megadim (quoting the Gra), and the Mekor Baruch.
Shiur provided courtesy of Torah Anytime
