What is the difference between דוד (David) and דויד (Dovid)

Greetings.

I will copy a question and answer from the great Rabbi Ben Ish Chai, zt"l, in his book Sodeh Yashar (Part 4 - Question 9):

“Question: Why is King David, peace be upon him, not written with an additional ’’י’’ (Yud) except in Chronicles and the Song of Songs, which are indeed written, but in the Prophets, he is not written with a yud? Let Him teach us, and His reward be doubled from Heaven.”

“Answer: In the Gate of the Divine Spirit, our Rabbi, the Arizal, of blessed memory, revealed the levels of prophecy, and it is stated there explicitly that prophecy, which is a voice within a voice, was attained only by Moses our Rabbi, peace be upon him, alone. And in contrast, in the Divine Spirit, King David, peace be upon him, achieved it alone, as it is a voice within a voice and both are his own. See there. Therefore, in the books of the Prophets, which were said through prophecy, the name of King David, peace be upon him, is not mentioned with a yud, because although he also attained greatness, he did not reach the level mentioned in prophecy. However, in the Writings, which are said through Divine Spirit and not through prophecy, his name is mentioned with an additional yud, hinting at the elevation and virtue that King David, peace be upon him, had over all other individuals given the Divine Spirit.”

“Furthermore, it seems to me that the reason his name is mentioned in the Writings, which are after the Prophets, with this addition and elevation of yud is to teach that in the end he attained a great advantage and elevation greater than what he had initially. And regarding him it is stated, ‘If your beginning was small, your end will greatly increase.’ For דויד (Dovid) with a yud equals twenty-four, and his name is doubled like the righteous, hence כ"ד, that the elevation and promise of the verse, ‘And I will establish your throne like the sun,’ will be fulfilled in King David, peace be upon him.

“However, it seems a great novelty that in the book of Ezekiel, Chapter 34, דויד (Dovid) is mentioned fully with a yud, as it is written: ‘And I will establish one shepherd over them, and he will feed them, my servant דויד (Dovid), he will feed them, etc.’ Here, דויד (Dovid) is written fully with a yud, even though it is a book of Prophets, and even though in the book of Ezekiel himself he is written several times without a yud, and in the aforementioned chapter, it is written without a yud—‘And the servants of דוד (David) will be princes among them.’ Nevertheless, דויד (Dovid) is mentioned with a yud only in the mentioned verse, as it is prophesied that the prophet Ezekiel, peace be upon him, gave a prophecy concerning the greatness he will achieve in the future to be called דויד (Dovid) fully with a י"ד.

“Thus, I wrote elsewhere that after the prayer for the new moon when they say, ‘David the King of Israel lives and endures,’ a person should intend דויד (Dovid) fully with a yud. And may Hashem illuminate our eyes with the light of His Torah. Amen, may it be His will.”

Until here.

And so wrote other sages of Kabbalah [in the book Megaleh Amukot on the Torah, Parashat Vayikra, section P"D, in the book Koheleth Yaakov - entry דו], that in the future he will be called by the name דויד (Dovid).

There is much elaboration in the other books of Kabbalah, and for now, we will suffice with this.

Wishing success - Menashe Israel