The spirit of God: translators should avoid reading into the Old Testament texts later Christian concepts concerning the Trinity. Though New International Version capitalizes the word spirit in this verse, it is preferable to follow the example of most translations and not capitalize. See also comments on 10.6.

Came mightily upon is a literal translation of the Hebrew. Receptor languages will have different ways of describing the action of a spirit taking control of someone. New Jewish Publication Society’s Tanakh renders this “the spirit of God gripped Saul.” Compare 10.10, where the same sort of expression is used.

His anger was greatly kindled: in this idiom anger is said to begin burning like a fire; it occurs also in 17.28; 20.30; 2 Sam 6.7; 12.5; 24.1. New Jewish Publication Society’s Tanakh, maintaining the imagery of the Hebrew, says “his anger blazed up.” New American Bible provides a nonfigurative translation model: “he became very angry.”

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on the First and Second Books of Samuel, Volume 1. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here .