How is the sense of hope developed in the poem?

Most of the hope in the poem "God's Grandeur" is evident in the second stanza. The first stanza describes how mankind has ignored the grandeur of God and, worse than that, has "trod . . . trod . . . trod" over it. In the first stanza, the speaker is angry that mankind has tainted God's grandeur and "seared (it) with trade" and "bleared (and) smeared (it) with toil."
In the second stanza, however, the speaker says that despite the fact that mankind has ignored and spoiled God's grandeur, there is still hope, because God's grandeur is infinite. In the first line the speaker says that "nature," which is the most obvious manifestation of God's grandeur, "is never spent." This immediately suggests that there is hope because there will always be an opportunity for redemption.
The speaker then uses an extended metaphor of sunset ("the last lights off the black West") and sunrise ("morning, at the brown brink eastward, springs") to suggest that, just as the sun will always rise and the light will replace the darkness, so too will God's grandeur always be there as a light to relieve the darkness.
At the end of the poem, we are given an image of God embracing the world "with warm breast." This paternal image suggests a caring, protective God. The implication is that, much as a parent might forgive, time and again, the sins of a child, so too will God forgive, time and again, the sins of mankind. This image emphasizes the point made at the beginning of the stanza—that God's mercy, grace, and grandeur are infinite. From this the speaker takes, and also offers, hope.