מלאך הברית

The Gemoro (Eruvin 43a) assumes that Eliyahu Hanavi cannot appear on Shabbos or Yom Tov, because of the איסור of חוץ לתחום. (if איסור תחומין is למעלה מעשרה )

How can we say at a Bris, on Shabbos & Yom Tov “זה הכסא של אליהו- עמוד על ימיני-?

The Shu”t Chasam Sofer (Chelek 6-98) explains that there are two parts to E.Hanavi. His

Guf (body) which is resting in גן עדן התחתון, in this world. The other part is his

Neshama, which went up to heaven and serves as a Malach.

At a Bris he appears as a Malach (מלאך הברית) from heaven. A Malach is not

obligated to keep the Mitzvohs. There also is no Din of Techumin from heaven to earth

(Tosfos 45b dh. Leima) .

When the time will come, Bimeheiro Veyomeinu to bring us the Besura of Higia Z’man

Geulaschem, E. Hanavi will appear with his Guf & Neshama.  at this stage, he is like any

Yid who is Mechuyav in Mitzvohs. He can’t come on Shabbos & Y.T. from Gan Eden

Hatachton which is Chutz L’tchum.

Tishbi Yetaretz Kushyos Uboyos will be with his Guf, therefore

we don’t have the problem of Lo Bashomayim Hie

Those who believe that E. Hanavi appears at the seder,

it can only be the Neshama (Guf can’t come from chutz l’tchum) אמבצי