The third stanza of Richard Lovelace’s poem titled “To Althea, from Prison,” reads as follows:
When (like committed linnets) I
With shriller throat shall sing
The sweetness, Mercy, Majesty,
And glories of my King; 
When I shall voice aloud how good
He is, how Great should be,
Enlargèd Winds, that curl the Flood,
Know no such Liberty.
This stanza might be paraphrased and analyzed in the following ways: when I (like encaged songbirds) sing even more loudly and forcefully than a bird could sing and when I use my singing to celebrate the goodness, compassion, and grandness of my king (King Charles I); and when I proclaim how virtuous he is and how great in power he should be (that is, if he were properly appreciated by his subjects, some of whom are rebelling against him); then, when all these events occur, not even the freely flowing winds that stir up waves on the sea will know no greater liberty than I know.
Paradoxically, the speaker in this stanza engages in the very kind of singing he imagines himself doing in the future. This stanza, then, calls a kind of subtle attention to the fact that he is already fulfilling the promises this stanza makes.
Notice the progression of the poem so far: from an emphasis on love of women (in stanza one), to an emphasis on fellowship with (probably male) friends (in stanza two); to an emphasis on love and loyalty to the king (in the present stanza). The poem is organized in such a way that it becomes progressively more serious and broader in its implications with each new stanza. In a sense, the poem also moves up the so-called “Great Chain of Being” (which explained the hierarchy of the universe). It is not surprising, then, that heavenly angels are mentioned in the fourth and final stanza.