ספר שמות

Another way of explaining the difference in syntax between ‎Moses “enthroning” G’d forever and David doing so, based on the ‎Talmud in Nedarim 10, runs as follows. The Talmud there ‎discusses the prohibition of our formulating even a praise of the ‎Lord by mentioning His name first. It is forbidden. For instance, ‎when making a vow, one must not say: ‎לה' חטאת‎ “for the Lord a ‎sin offering,” but must be careful to mention the words “sin ‎offering” before adding the words: “for the Lord.” The reason for ‎the prohibition is that if the donor were to die before completing ‎his sentence, he would have been guilty of transgressing the third ‎of the Ten Commandments, which warns us not to utter the ‎name of the Lord in vain, as this is a sin that cannot be ‎completely forgiven even if you do teshuvah. David was ‎conscious of this halachah and that is why he prefaced his ‎praise of the Lord with the word: ‎ימלוך‎, “may He reign.At the time when Moses intoned the song at the shores of the ‎sea of reeds, the Israelites had become free from any ritual ‎impurity that had contaminated them prior to that experience, ‎so that, angel-like, they were not subject to the laws that restrict ‎man. (Compare Sh’mot Rabbah 32,1). After the sin of the ‎golden calf, when ritual contamination again affected the people, ‎the prohibition to commence a sentence with mentioning the ‎holy name of the Lord was re-introduced.‎