What is the origin of the idiom "woe is someone" and when to use it?

The idiom "woe is someone" has its roots in Old English and Middle English literature. It reflects a time when English speakers used more elaborate and poetic language to convey complex emotions and sentiments. In this idiom, "woe" refers to a deep feeling of sorrow, distress, or misery, and it is typically followed by "is" to indicate that the sorrow or distress belongs to someone. It is often employed to express a deep sense of sorrow, distress, or misfortune that has befallen someone, and it conveys a degree of empathy or sympathy towards that person's plight.