In this poem, what is the significance of the poet’s comparison of love to "childhood’s faith"?

sonnet 43
by elizabeth barrett browning

how do i love thee? let me count the ways.
i love thee to the depth and breadth and height
my soul can reach, when feeling out of sight
for the ends of being and ideal grace.
i love thee to the level of every day’s
most quiet need, by sun and candle-light.
i love thee freely, as men strive for right;
i love thee purely, as they turn from praise.
i love thee with the passion put to use
in my old griefs, and with my childhood’s faith.
i love thee with a love i seemed to lose
with my lost saints. i love thee with the breath,
smiles, tears, of all my life; and, if god choose,
i shall but love thee better after death.