We know from the story of the akeidah that Yitzchak was brought to Eretz HaMoriya (Braishis 22:2). Where is this land or mountain? Rashi notes that Har HaMoriya is identified elsewhere as the Har haBayis; Shlomo is described (Divrei haYamim II 3:1) as building the Mikdash “b’Yerushalayim b’Har haMoriya”. The Rambam codifies l’halacha (Bais haBechira 2:1) that the place of the mizbayach in the Mikdash is identical with the location of akeidas Yitzchak.
Given that background, there is a very difficult Tosfos in Ta’anis 16a . The gemara darshens the name Moriya as “the place which caused fear (=morah) to the Nations”. Tosfos writes that Har haMoriya is Har Sinai and the fear is the fear of mattan Torah. How could that be? Har Sinai is not in Eretz Yisrael, and certainly not near the makom mikdash! Meforshim struggle with this one… My son suggested that there are two places names Har haMoriya. Though Tosfos sometimes suggests answers like this (e.g. Gittin 2a d”h Ashkelon), it would be quite a chiddush.