The structure of Revised Standard Version, which closely follows the Hebrew, reverses the normal English order, but this is inverted in Good News Translation to make it more natural. As noted in the comments at the end of verse 21, the alternative translation in Parola Del Signore: La Bibbia in Lingua Corrente connects From the blood of the slain to the statements about Saul’s shield. Others (Traduction œcuménique de la Bible, Chouraqui, Maredsous, Nueva Biblia Española,Parola Del Signore: La Bibbia in Lingua Corrente) connect both From the blood of the slain and from the fat of the mighty to the end of verse 21, and this solution is preferable to that in Revised Standard Version and Good News Translation. This is the solution also of La Bible Pléiade, which renders verses 21a and 22 as follows:

• The shield of Saul wasn’t anointed with oil,
but with the blood of the wounded, with the fat of the heroes.
The bow of Jonathan did not turn back
and the sword of Saul did not return without success.

The bow of Jonathan and the sword of Saul are almost given personal characteristics that properly belong to their owners. It is, in fact, Jonathan who did not retreat and Saul who did not return from battle without having killed his enemies. In some languages it may be more natural to focus on Jonathan and Saul rather than retaining their weapons as subjects of the verbs: “Jonathan was very accurate with his bow, and Saul killed many people with his sword….”

The fat of the mighty: the mighty refers here to the enemy soldiers, though in verses 19, 21, 25, and 27 the same Hebrew word refers to Saul and Jonathan. Rather than translate literally the words the fat of, Revised English Bible says “the breast of,” and New American Bible says “the bodies of.” The laws of Leviticus forbid the eating of fat and blood. The fat and blood from animals was to be offered as a sacrifice to God. The use of blood and fat here should be understood in this context, that is, killing of the enemies was understand as a sacrificial offering presented to God. This cultural information cannot easily be included in the translation itself, but may be added in study Bible notes. Unlike most English translations, Fox follows several ancient versions in reading “the sword of the mighty” instead of the fat of the mighty. In Hebrew the word for “sword” (cherev) and the word for “fat” (chelev) are similar. Such a translation makes good sense, but so does the Masoretic Text, so the Masoretic Text should be followed here.

Returned not empty: the place of return is not stated. Revised English Bible most likely expresses the correct meaning, “never returned empty to the scabbard.” Perhaps a literal translation will not mean that Saul was successful in battle. Compare New American Bible (“did not return unstained”) and La Bible Pléiade (“did not return without success”).

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on the First and Second Books of Samuel, Volume 2. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here .