What is the meaning of Revelation 6:9?

* The two F.O.G. Bibles & Commentary below are currently a work in progress.

And when the Lamb opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony they had upheld.

Berean Standard Bible (BSB)

When he opened the fifth seal, I saw underneath the altar the souls of those who had been killed for the Word of God, and for the testimony of the Lamb which they had.

World English Bible (WEB)

And{G2532} when{G3753} he had opened{G455}{(G5656)} the fifth{G3991} seal{G4973}, I saw{G1492}{(G5627)} under{G5270} the altar{G2379} the souls{G5590} of them that were slain{G4969}{(G5772)} for{G1223} the word{G3056} of God{G2316}, and{G2532} for{G1223} the testimony{G3141} which{G3739} they held{G2192}{(G5707)}:

Strong's King James

(9) When breaking the fifth seal, I saw underneath the altar, the lives of them slain because of The Word of אֱלֹהִים Elohim, because of the testimony that they have.

The F.O.G*

[9] When He broke the fifth seal, I saw under the altar the souls of those who had been slaughtered for faithfully proclaiming God's word and maintaining their testimony.

The F.O.G Paraphrase

And when he opened the fifth seal, I saw under the altar the souls of those slain because of the word of God, and because of the testimony that they held,

Young's Literal Translation