Charles Ellicott Commentary Isaiah 38:14

"Like a swallow [or] a crane, so did I chatter; I did moan as a dove; mine eyes fail [with looking] upward: O Lord, I am oppressed, be thou my surety." — Isaiah 38:14 (ASV)

Like a crane ... — The three birds—strictly, the “swift,” the “crane,” the “dove”—each with its special note of lamentation, represent, so to speak, the cries of pain and the low, suppressed wail of the sufferer. The three appear again together in Jeremiah 8:7.

Undertake for me — That is, as in Genesis 43:9; Genesis 44:32; and Job 17:3, Be surety for me. The idea is that of Death, who, in another sense, is nevertheless only the minister of Jehovah, as the creditor pressing for immediate payment. The words involve (as Cheyne points out) something like an appeal to the judge, who is also the accuser, to be bail for the accused.