This can be reworded so that the abstract nouns "justice" and "strength" are expressed as adjectives. Alternate translation: "people. Yahweh will cause the judges to be just and will cause to be strong those who" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
A person who has a "spirit of justice" is someone who has the characteristic of justice and is a just person. (See: [[rc://en/ta/man/translate/figs-idiom]])
# sits in judgment
This idiom means the person has the authority to judge. (See: [[rc://en/ta/man/translate/figs-idiom]])
# strength for those who turn back their enemies at their gates
Here "to turn back" is an idiom that means to defeat in battle. Alternate translation: "Yahweh will cause the soldiers to be strong so that they defeat their enemies when the enemies attack their city" (See: [[rc://en/ta/man/translate/figs-idiom]])