ZAʿMAN LA-ʿAMRU ABĪKI LAYSA BI-MAZʿAM
A claim—by your father’s life—yet not an empty assertion.
La-ʿamru belongs to an Arabic oath formula. The bi- in bi-mazʿam, after negation, adds emphasis.
The related words zaʿman/mazʿam echo one another in sound and derivation. Their rhetorical effect nevertheless depends on the full argument, not the recurrence of a root alone.