Sefer HaChinuch ספר החינוך

To not take steps on the altar: To not ascend the altar with stairs, so that he not make large steps in his going up — as it is stated (Exodus 20:23), “And you shall not ascend My altar by stairs, that your nakedness not be exposed upon it.” Rather, when he ascends there, he should walk slowly and with awe, [placing] his heel in front of his toe. And so is it said in the Mekhilta DeRabbi Yishmael 20:23.

That which we have written in the commandment that is before it is from the roots of this commandment — to fix the awe of the place and its importance in our souls. And, therefore, we were warned not to act with light-headedness there in any way. And everyone knows that the stones would not be exacting about any disgrace [to them], since they do not see and do not hear. Rather, the whole matter is to give an illustration in our heart of the awe of the place and its importance and great glory — as through action, the heart is activated, as we have written.

The laws of the commandment — how we make the ramp so that they will not come to transgressing this negative commandment, its form and all of its content — are elucidated in the third chapter of Middot. (See Mishneh Torah, Laws of The Chosen Temple 2:13.)

And [it] is practiced at the time of the [Temple] by males and females. And one who transgresses it and takes a large step, to the point that he reveals his nakedness on the altar, is lashed. And “the humble ones will dwell in the Land.”