The OED includes a specific sense of this usage of introductory and, and provides early examples from hymns and poems, citing works by Thomas Wyatt, Isaac Watts, John Wesley, and Charles Wesley. This usage is grammatical, though it follows an older stylistic convention, particularly common in verse, hymns, and elevated or rhetorical language.

Here is the definition along with the three earliest citations from the OED:

In expressing doubt at, or asking the truth of, what one has already heard.
Frequent in earlier use in verse, esp. in poems of lament or elegy.