While the second stanza portrays death as something calm that one can anticipate, this final stanza shows life as “weary strife” and a “benighted tempest.” This last line signals the change that has taken over the speaker. After the death of her loved one, she sees life as a painful thing to endure and death as peaceful.
In this final stanza, the speaker begins using the collective “we” pronoun to describe her loss. This shift in pronoun usage signifies that she identifies with the dead subject. She experiences both the literal death of her subject and her own symbolic death. In this way, the speaker makes the death of her subject a shared experience: her loss becomes death itself as part of her dies with the person she loves.
Notice that the speaker does not specifically identify for what she is thanking God. It’s possible that from context readers could deduce what the speaker is thankful for; however, the ambiguity of the subject of these two lines suggests that on one level the speaker is blindly thanking God: the death and the aftermath of the death are so out of her control that all she can do is turn to God.
"then to thank God..."See in text(Text of the Poem)
The speaker thanks God for taking away her beloved subject presumably because the subject was in so much pain. Death is portrayed as a mercy, something to be celebrated, in this final stanza.
In English, the present-perfect verb construction “I have lived” describes attributes or experiences rather than completed actions. In using this form, the speaker suggests that this experience of her sister’s dying hour is a part of her. She has experienced death as if it were her own parting hour by being in the presence of her sister’s parting hour.
"little terror in the grave..."See in text(Text of the Poem)
By “little terror in the grave,” the speaker means that she is no longer afraid of death. Now, life is the joyless, terrifying experience while death holds comfort for her. This sets up one of the main themes of this poem: after the loss of a loved one, death represents peace while life contains pain.