Death, be not proud

The pattern of this poem is closely related to the English and Italian sonnet models.  Each quatrain is a sentence, and the poem is divided into three stanzas with a two-line concluding sentence.  If I were to guess which one it is closer to, then I would guess the English model because that model makes the big point at the end.  I believe the speaker of this poem is a man of assured faith with firm conviction that death is not to be feared.  He seems to be pretty confident in his reasoning and not trying to convince himself that death is nothing to be afraid of.  The second to last line states "one short sleep passed, we wake eternally."  Is this a reference to heaven?  We sleep for a short time then end up in heaven.