The Wikipedia has a nice entry on this famous Robert Browning poem:

It is not a biography of Abraham ibn Ezra; like all of Browning’s historical poems, it is a free interpretation of the idea that Ezra’s life and work suggests to Browning, but the poem is Robert Browning using Ezra as a mouthpiece, not the other way around. At the center of the poem is a theistic paradox, that good might lie in the inevitability of its absence:

For thence,—a paradox
Which comforts while it mocks,—
Shall life succeed in that it seems to fail:
What I aspired to be,
And was not, comforts me:
brute I might have been, but would not sink i’ the scale.

Reminds me of the saying that the best security is the stuff that is rarely or never seen.

Amazing how good Wikipedia can be sometimes.