Sforno on Genesis 22:14/ספורנו על בראשית כ״ב:י״ד

1אשר יאמר היום, the place of which the Israelites had said on the day that the Torah was written (or given) that G’d manifests Himself on the mountain. G’d would reveal which mountain this is only in the future, in the days of David, seeing that even in Deuteronomy 12,11 only veiled reference is made to such a mountain. It was this mountain, subsequently known as the Temple Mount which Avraham now named ה' יראה.