Judges 8:19

19 And Gedeon said, They were my brethren and the sons of my mother: the Lord lives, if ye had preserved them alive, I would not have slain you.

Judges 8:19 Meaning and Commentary

Judges 8:19

And he said, they were my brethren, even the sons of my
mother
His brethren by his mother's side, but not by his father's side; or the phrase

the sons of my mother is added,
to show that he did not mean brethren in a large sense, as all the Israelites were, but in a strict sense, being so nearly related as his mother's children:

as the Lord liveth, if ye had saved them alive, I would not slay you;
for not being Canaanites, he was not obliged by the law of God to put them to death, and by the law of nations, as they had surrendered themselves, and were made prisoners of war, they ought to have been saved; but as they appeared to be murderers, and had slain the Israelites in cold blood, they deserved to die; and the persons they had slain being Gideon's brethren, he was the avenger of blood, and it became him to put them to death.

Judges 8:19 In-Context

17 And he overthrew the tower of Phanuel, and slew the men of the city.
18 And he said to Zebee and Salmana, Where the men whom ye slew in Thabor? and they said, As thou, so they, according to the likeness of the son of a king.
19 And Gedeon said, They were my brethren and the sons of my mother: the Lord lives, if ye had preserved them alive, I would not have slain you.
20 And he said to Jether his first-born, Rise and slay them; but the lad drew not his sword, for he was afraid, for he was yet very young.
21 And Zebee and Salmana said, Rise thou and fall upon us, for thy power as that of a man; and Gedeon arose, and slew Zebee and Salmana: and he took the round ornaments that were on the necks of their camels.

The Brenton translation of the Septuagint is in the public domain.