C. F. Keil and Franz Delitzsch on 2 Kings 5:13

2Ki 5:13

His servants then addressed him in a friendly manner, and said, “My father, if the prophet had said to thee a great thing (i.e., a thing difficult to carry out), shouldst thou not have done it? how much more then, since he has said to thee, Wash, and thou wilt be clean?” אבי, my father, is a confidential expression arising from childlike piety, as in 2Ki 6:21 and 1Sa 24:12; and the etymological jugglery which traces אבי from לבי = לוי = לוּ (Ewald, Gr. §358, Anm.), or from אם (Thenius), is quite superfluous (see Delitzsch on Job, vol. ii. p. 265, transl.). - דּבּר...גּדול דּבר is a conditional clause without אם (see Ewald, §357, b.), and the object is placed first for the sake of emphasis (according to Ewald, §309, a.). כּי אף, how much more (see Ewald, §354, c.), sc. shouldst thou do what is required, since he has ordered thee so small and easy a thing.