What is the conclusion of the poem "Easter Wings"?

Each of the two stanzas begins with a tone of sadness and regret due to the sinful nature of the world. Halfway through each stanza, the tone shifts at the words "with thee" (meaning with God) to a tone of hope and a spirit of overcoming.
In the conclusion of the poem, the speaker wants to feel the victory over sin and difficulty through God. Returning to metaphor of the bird which both provides the winglike shape of the poem and is referenced as a lark in the first stanza, the speaker hopes to join his "wings" to that of his Creator and thereby soar over his personal (and very human) adversity. With God's help, "affliction shall advance the flight in [him]." His difficulty will thereby strengthen his flight, or path, as he leans into the guidance of God.