Commentary
Those are the news of the conditional, and indeed, We do not waste. You may consider 'Indeed, We do not waste' and 'Those' as two pieces of news together. Or you may consider 'Those' as a statement that clarifies the ambiguous reward. If you say: If you consider 'Indeed, We do not waste' as news, where is the pronoun referring back to the subject? I say: 'Whoever does good deeds' and 'those who believe and do righteous deeds' are encompassed by one meaning, so 'Whoever does good' stands in place of the pronoun. Or you meant: 'Whoever does good among them,' which is like saying: 'The butter is worth a dirham.' The first is for beginning, and the second is for clarification.
And the indefinite article for 'bracelets' is for the ambiguity of their beauty. And it combines between 'silk' which is the fine type of brocade, and 'brocade' which is the thick type, combining between the two types. And it specifically mentions reclining, because it is the posture of the blessed and the kings on their couches.
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