This expression means "extremely old". It comes from the Bible, precisely from Job 15:7, where it says "Are you the first man that ever was born? Or were you made before the hills?" During the 18th century, it was introduced into the English language as a fixed expression originating from those words, with the meaning that we know nowadays.

Esta expresión significa "extremadamente viejo". Proviene de la Biblia, más precisamente de Job 15, 7, donde dice "¿Eres el primer hombre que ha nacido? O ¿fuiste creado antes que las colinas?". Durante el siglo XVIII, se introdujo al idioma inglés como una expresión fija originada a partir de esas palabras, con el significado que conocemos hoy en día.