«طَعَنَ عَنْهَا سِرًّا وَهَلُمَّ جَرًّا»
He went away from her secretly, and so the matter continued.
Here ṭaʿana ʿanhā describes departing from her, not the common literal sense of stabbing with a spear. Sirrā means secretly; halumma jarrā is a colloquial idiom equivalent to “and so on.”
A very short phrase carries a serious consequence: the husband disappears, leaving mother and child uncertain of his fate.