הדיבוק

וְר֧וּחַ יְהֹוָ֛ה סָ֖רָה מֵעִ֣ם שָׁא֑וּל וּבִעֲתַ֥תּוּ רֽוּחַ־רָעָ֖ה מֵאֵ֥ת יְהֹוָֽה׃

Now the spirit of the LORD had departed from Saul, and an evil spirit from the LORD terrified him.

Not a dybbuk: the spirit comes “from the LORD” and is no dead soul.

עברית: Miqra according to the Masorah (CC-BY-SA)אנגלית: The Holy Scriptures: A New Translation (JPS 1917) (Public Domain)

ספריא ↗מכון ממרא ↗חב״ד ↗

… הנה בחי' העבור היא בחיים כנז"ל, ר"ל, כי לפעמים יזדמן ליד האדם איזו מצוה, ויעשנה כתקנה, ואז יזדמן לו נפש אחד, מן איזה צדיק קדמון, שעשה אותה המצוה עצמה כתקנה, וכיון שנתדמו יחד בענין מצוה זאת, יתעבר בו נפש הצדיק ההוא. …

… Here, regarding Ibur, this [happens] during the life of a person (as explained in Hakdama 2). I wanted to say, that sometimes a person will merit through some mitzvah, and this makes a rectification. And through this rectification, he receives another Nefesh from an ancient Tzaddik (which already departed from the world). This Tzaddik [has a similarity to him in that he also] did the same mitzvah, and when the person does the mitzvah, the Nefesh of the Tzaddik enters into him …

Kabbalistic theory of the 16th century (Chaim Vital, recording the Arizal). This is the benign ibbur. The malign possessing spirit called a dybbuk comes from later folklore.

עברית: Shaar HaGilgulim (Public Domain)אנגלית: Sefaria Community Translation (CC0)

ספריא ↗

וְרוּחַ גְבוּרָה מִן קֳדָם יְיָ דַהֲוַת עִם שָׁאוּל עֲדָת מִנֵיהּ וּמְבַעֲתָא לֵיהּ רוּחַ בִּישָׁא מִן קֳדָם יְיָ:

And the mighty spirit from before the LORD who had been with Saul, departed from him; and an evil spirit from before the LORD tormented him.

עברית: Mikraot Gedolot (Public Domain)אנגלית: The Targum of Samuel; trans. E. van Staalduine-Sulman. Leiden: Brill, 2002 (CC-BY-NC)

ספריא ↗