Qatadah said concerning this verse: "On that Day Allah will pay them in full their true recompense" [Surah al-Nur: 25]: He will give the people of truth their due (recompense), and the people of falsehood their falsehood (as recompense), and they will know that Allah is the Truth, the Manifest.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19539
Ibn Abbas (may Allah be pleased with them both) said in the explanation of this saying of Allah Almighty: "On that Day Allah will pay them in full their true recompense" [al-Nur: 25], that is, We will recompense them for their deeds with truth; just as He recompenses His friends with reward, so He recompenses His enemies with punishment. "And they will know" [al-Nur: 25], that is, on the Day of Resurrection, "that Allah is the Truth, the Manifest" [al-Nur: 25]. The reason for this is that Abdullah bin Ubayy bin Salul was in doubt about the religion and he was the chief of the hypocrites; what is meant is that the doubt left him and he became certain, at a time when that certainty could not benefit him.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19540
Sa'id bin Jubayr said: "On that Day" [Surah al-Nur: 25], that is, in the Hereafter, "Allah will pay them in full their true recompense" [Surah al-Nur: 25]: that is, He will reckon with them in justice and will not wrong them. "And they will know that Allah is the Truth, the Manifest" [Surah al-Nur: 25]: that is, the One whose justice is manifest.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19541