It is not a symbol of _a truth_ at all, but of _a fact_, of the infinitely grandest fact in the universe, which is itself the outcome and symbol of the grandest Truth.
_The Cross_ is an historical _sign_, not properly _a symbol_, except through the facts it reminds us of.

On the other hand, _baptism_ and the _eucharist_ are symbols of the loftiest and profoundest kind, true to nature and all its meanings, as well as to the facts of which they remind us.

They are in themselves symbols of the truths involved in the facts they commemorate.
Of Nature's symbols George Herbert has made large use; but he would have been yet a greater poet if he had made a larger use of them still.

Then at least we might have got rid of such oddities as the stanzas for steps up to the church-door, the first at the bottom of the page; of the lines shaped into ugly altar-form; and of the absurd Easter wings, made of ever lengthening lines.

This would not have been much, I confess, nor the gain by their loss great; but not to mention the larger supply of images graceful with the grace of God, who when he had made them said they were good, it would have led to the further purification of his taste, perhaps even to the casting out of all that could untimely move our mirth; until possibly (for illustration), instead of this lovely stanza, he would have given us even a lovelier: Listen, sweet dove, unto my song, And spread thy golden wings on me; Hatching my tender heart so long, Till it get wing, and fly away with thee.
The stanza is indeed lovely, and true and tender and clever as well; yet who can help smiling at the notion of the incubation of the heart-egg, although what the poet means is so good that the smile almost vanishes in a sigh?
There is no doubt that the works of man's hands will also afford many true symbols; but I do think that, in proportion as a man gives himself to those instead of studying Truth's wardrobe of forms in nature, so will he decline from the high calling of the poet.