Exodus 20:26

Steps are prohibited, because the command is addressed to the Israelite in general, who would sacrifice in his ordinary dress. In later times, when altars of larger size were constructed, a ledge (see on Exodus 27:5), or steps (Ezekiel 43:17), came into use: but sacrifice was then confined to the priests, and exposure of the person was guarded against in their case by linen drawers being specially prescribed for their use (Exodus 28:42). Cf. OTJC.2 [183] p. 358.

[183] W. R. Smith, Old Testament in the Jewish Church, ed. 2, 1892.