OET interlinear REV 7:14

uW Translation Notes:

Note 1 topic: writing-politeness

κύριέ μου, σὺ οἶδας

(Some words not found in SR-GNT: Καί εἴρηκα αὐτῷ Κύριε μού σύ οἶδας Καί εἶπεν μοί Οὗτοι εἰσίν οἱ ἐρχόμενοι ἐκ τῆς θλίψεως τῆς μεγάλης καί ἔπλυναν τάς στολάς αὐτῶν καί ἐλεύκαναν αὐτάς ἐν τῷ αἵματι τοῦ Ἀρνίου)

John is answering the elder politely. You may translate this the way someone would respond politely in your language to a question whose answer they did not know. Alternate translation: [I do not know, please tell me]

Note 2 topic: figures-of-speech / abstractnouns

τῆς θλίψεως τῆς μεγάλης

the tribulation ¬the great

If your language does not use an abstract noun for the idea of tribulatron, you could express the same idea in another way. Alternate translation: [the time when believers in Jesus will be greatly persecuted]

Note 3 topic: figures-of-speech / metaphor

ἔπλυναν τὰς στολὰς αὐτῶν, καὶ ἐλεύκαναν αὐτὰς ἐν τῷ αἵματι τοῦ Ἀρνίου

˱they˲_washed (Some words not found in SR-GNT: Καί εἴρηκα αὐτῷ Κύριε μού σύ οἶδας Καί εἶπεν μοί Οὗτοι εἰσίν οἱ ἐρχόμενοι ἐκ τῆς θλίψεως τῆς μεγάλης καί ἔπλυναν τάς στολάς αὐτῶν καί ἐλεύκαναν αὐτάς ἐν τῷ αἵματι τοῦ Ἀρνίου)

As in [3:4](../03/04.md) and other passages in the book, robes that are white represent purity of life and devotion to Jesus. The blood of the Lamb is the blood that Jesus shed when he died on the cross as the Savior. If it would be clearer in your language, you could state the meaning plainly. The UST models one way to do this.