Songs of Songs 5:16 is NOT a prophecy about Muhammad.
“His mouth is most sweet; yea, he is altogether lovely. This is my beloved, and this is my friend, O daughters of Jerusalem.'”
Song Of Songs 5:16 Tanakh Bible
This is obviously a love song between Solomon and his bride, and to put Muhammad in the place of the bride’s beloved turns the book into nonsense. The context is clearly about the passionate love of a marriage and is sometimes rather descriptive. It could not possibly be about some future prophet bringing a new book.
Additionally, the argument hinges on the idea that, in the original Hebrew, the personal name of Muhammad is there. It plainly is not. The Hebrew word “machmad” means “desirable” or when used as a noun, “desirable thing” or “lovely thing.” The plural form used here, “machamadim,” is an emphatic form and so is translated “wholly desirable” or “altogether lovely.” The fact that it sounds kind of like a name in another language from a different time period is obviously irrelevant to the meaning of the word.
This word is used throughout the Old Testament. It is not a unique word. If the word secretly means the personal name “Muhammad,” then in places like Hosea 9:16 where God pronounces judgment on Ephraim and promises to slay even “your beloved” (machamadim) we should read this as a promise by God that He would slay Muhammad in judgment, right?