Antecedent of a pronoun in Byron's "The Bride of Abydos"

Question

What is the antecedent of the pronoun they in the context below, from Byron's The Bride of Abydos, Canto I, stanza 5?

He is an Arab to my sight, *
Or Christian crouching in the fight. – (145)
But hark! – I hear Zuleika’s voice,
Like Houris’ hymn it meets mine ear;
She is the offspring of my choice –
Oh! more than even her mother dear,
With all to hope, and nought to fear, (150)
My Peri! – ever welcome here!
Sweet, as the desart-fountain’s wave,
To lips just cooled in time to save –
Such to my longing sight art thou;
Nor can they waft to Mecca’s shrine (155)
More thanks for life, than I for thine
Who blest thy birth, and bless thee now.”

Full poem here

Answer 1

The antecedent of they here is lips.

My Peri! – ever welcome here!
Sweet, as the desart-fountain’s wave,
To lips just cooled in time to save –
Such to my longing sight art thou;
Nor can they waft to Mecca’s shrine (155)
More thanks for life, than I for thine
Who blest thy birth, and bless thee now.”

What this is saying is that the speaker thinks Zuleika (his "Peri") is as sweet to his sight as an oasis's water is sweet to the lips of a man dying of thirst in the desert. And further, that the lips of this dying man could not give more thanks for the water that saved his life than the speaker's thanks for Zuleika's existence.

Using an antecedent inside a parenthetical comment is somewhat unusual grammatically, but Byron does similar things at other places in this poem. For example, in the lines

That – let the old and weary sleep –
I could not; and to view alone

"I could not" means "I could not sleep"; here "could not" refers back to "sleep", which is also in a parenthetical comment.

Answer 2

He is talking about the muslims who waft-pass through- mecca's shrine.