In Shakespeare's language, the lines about a pocket speaking and falsely pocketing up a report highlight themes of dishonesty and corruption, suggesting the person in question is not trustworthy and that their lies are akin to palpable objects.
The lines "If but one of his pockets could speak, would it not say he lies? Ay, or very falsely pocket up his report" suggest that if the person's pocket, which could be holding bribes or ill-gotten gains, could testify, it would reveal the person's dishonesty by either affirming he lies or by dishonestly concealing (pocketing) the true account of events.
It reflects on themes of misrepresentation and corruption, often explored in Shakespeare's works. A character may be hinting at another's lack of integrity, suggesting that they are not trustworthy and that their falsehoods are as tangible as objects one could pocket.
Macbeth and the Tempest are rife with such rich, metaphorical language, challenging readers to consider deeper meanings beyond the literal words. Thus, interpreting these lines requires understanding the language and context in which they're spoken within the plays.