The 80th prohibition is that we are forbidden from ascending an altar which has stairs, in order to avoid taking broad steps when going up. One should rather walk "heel to toe."1
The source of this mitzvah is G‑d's statement2 (exalted be He), "Do not climb My altar with steps [so that your nakedness not be revealed on it]."
The Mechilta3 says, "What is the meaning of the phrase, 'so that your nakedness not be revealed on it'? It means that when one walks up to the altar, he should not take broad steps but walk 'heel to toe.' "
The form of the ramp and how it is built is explained in the third chapter of tractate Middos.4
The punishment for taking broad steps — to the extent of revealing one's nakedness — when walking up the altar is lashes.
