‘ And Jotham ran away, and fled, and went to Beer, and dwelt there for fear of Abimelech his brother.'
Having delivered his curse Jotham fled for his life. He journeyed to Beer, which means ‘a well' and there he lived for fear of Abimelech ‘his brother'. The last words are sardonic. A brother indeed! But he found refreshment, while finally his brother would receive none. The place is unknown and was probably intended to remain unknown. (‘Beer' would normally have another name attached e.g Beer-sheba). What mattered was that he had found refuge.
We are intended to see in this curse the hand of Yahweh. He was not pleased with the course that events had taken and would act accordingly. He was not powerless to act like Baal (Judges 6:31-32). But the writer does not want to mention His name in such a passage. He wants us to recognise that Abimelech was God-forsaken.