John Chrysostom

"Then Returned They," it is said: namely, when they had heard. For they could not have borne it, if the angel had not referred them to another Coming. It seems to me, that it was also on a sabbath-day that these things took place; for he would not thus have specified the distance, saying, "from the mount called Olivet, which is from Jerusalem a sabbath day's journey," unless they were then going on the sabbath-day a certain definite distance. …

Homily on Acts 3 ↗

Theophylact of Ohrid

When did "then they returned"? When they heard what was said by the Angels, because they would never have torn themselves away from the place if the Angels had not informed them about the second coming. And it seems to me that this happened on a Sabbath, because Luke would not have indicated the distance in this way: "from the mount called Olivet, which is near Jerusalem, a Sabbath day's journey away." The length of the journey that Jews were permitted to travel on the Sabbath day was fixed. …

Commentary on Acts ↗

Oecumenius

One mile, which was the distance of the Sabbath's journey, as Origen says in the fifth Homily, was two thousand cubits. And moreover the holy tent and the ark occupied this same space before the encampment, and from that distance they encamped. The distance permitted those who worshipped the holy tent to walk on the Sabbath.

Commentary on Acts ↗

Bede

He is near Jerusalem, having the distance of a Sabbath journey. According to history, it indicates that the Mount of Olives is separated by about a mile from the city of Jerusalem. For on the Sabbath, according to the law, it was not permitted to go more than a thousand paces. But according to allegory, whoever will be worthy to contemplate within the glory of the Lord ascending to the Father and to be enriched with the promise of the Holy Spirit, this one enters the city of eternal peace by the journey of the Sabbath. …

Commentary on Acts ↗