What is the difference between His, the Almighty's, saying "and the Sabaeans" (wal-sabi'een) and His saying "and the Sabaeans" (wal-sabi'oon)?

The two words have the same meaning, and the problem of the رفع (nominative case) of "al-Sabi'un" in Surat Al-Ma'idah is solved by considering it to be in the nominative case as a mubtada' (subject of a nominal sentence).