Read the last stanza of "Mutability.”It is the same!—For, be it joy or sorrow, The path of its departure still is free: Man’s yesterday may ne’er be like his morrow; Nought may endure but Mutability.

The stanza says that whether life brings joy or sorrow, each passes away, and that yesterday may never be like tomorrow. The final line, “Nought may endure but Mutability,” means that change is the only lasting thing. So the stanza’s main idea is that life is fleeting and constantly changing.

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