"You shall not build it of hewn stones, for your sword [you have lifted upon it...]"—Exodus 20:22.
It is forbidden to construct the Temple Altar of stones that have been touched by iron. If, indeed, the altar was constructed of such stones, it is invalid for sacrificial use.
"You shall not go up by steps to My altar"—Exodus 20:23.
We are forbidden from ascending the Temple Altar with stairs, in order to avoid taking broad steps when going up. Rather, one should walk up the altar on a ramp, going "heel to toe" (i.e. using small, humble steps).