Midrasch zu Jeschijahu 23:4

(to be understood as following "how much more so, etc." [before the preceding paragraph]:) And thus is it written (Isaiah 23:4) "Be ashamed, O Tziddon, for the sea has spoken, the fortress of the sea, saying: I have not labored, and I have not borne, and I have not raised youths or reared maidens." The sea hereby says: I, who do not fear — "perhaps I will not labor, perhaps I will not bear sons and daughters, perhaps I will bury sons and daughters" — What shall I say? "Will you not fear Me, says the L-rd. Will you not tremble before Me, who have set sand as a bound to the sea, an eternal law, not to be broken" — Now if I (the sea), with whom all of these trepidations do not obtain, do the will of my Master (and do not venture to break my bounds), how much more so you — "Be ashamed, O Tziddon!"