“Self-reverence, self-knowledge, self-control, These three alone lead life to sovereign power.”
Tennyson joins respect for oneself with knowledge and restraint: durable personal power is presented as the result of living by an inward law rather than seeking power merely for its own sake.
Source details
Oenone, in The Early Poems of Alfred, Lord Tennyson, Project Gutenberg #8601. Pallas speaks the lines while arguing that self-reverence, self-knowledge and self-control lead to a life governed by right rather than by reward; this is poetic character speech, not a prose maxim detached from the poem.