“Provisions made by a son to his father ob pias causas are those which proceed from the affectionate regard and natural duty which the son is bound morally to render to his father.” John Trayner, Trayner’s Latin Maxims 412 (4th ed. 1894).
ob pias causas
ob pias causas (ob pI-[schwa]s kaw-z[schwa]s). [Latin] Hist. On account of religious or charitable reasons; for dutiful considerations.