Arise, and go toward the south - How circumstantially particular are these directions! Every thing is so precisely marked that there is no danger of the apostle missing his way. He is to perform some great duty; but what, he is not informed. The road which he is to take is marked out; but what he is to do in that road, or how far he is to proceed, he is not told! It is God who employs him, and requires of him implicit obedience. If he do his will, according to the present direction, he shall know, by the issue, that God hath sent him on an errand worthy of his wisdom and goodness. We have a similar instance of circumstantial direction from God in Acts 9:11 : Arise, go into the street called Straight, and inquire in the house of Judas for one Saul of Tarsus, etc. And another instance, still more particular, in Acts 10:5, Acts 10:6 : Send men to Joppa, and call for one Simon, whose surname is Peter; he lodgeth with one Simon, a tanner, whose house is by the sea side. God never sends any man on a message, without giving him such directions as shall prevent all mistakes and miscarriages, if simply and implicitly followed. This is also strictly true of the doctrines contained in his word: no soul ever missed salvation that simply followed the directions given in the word of God. Those who will refine upon every thing, question the Divine testimony, and dispute with their Maker, cannot be saved. And how many of this stamp are found, even among Christians, professing strict godliness!

Gaza, which is desert - Αὑτη εϚιν ερημος, This it the desert, or this is in the desert. Gaza was a town about two miles and a half from the sea-side; it was the last town which a traveler passed through, when he went from Phoenicia to Egypt, and was at the entrance into a wilderness, according to the account given by Arrian in Exped. Alex. lib. ii. cap. 26, p. 102. [Ed. Gronov.]

That it was the last inhabited town, as a man goes from Phoenicia to Egypt, επι τῃ αρχῃ της Ερημου, on the commencement of the desert. See Bp. Pearce.

Dr. Lightfoot supposes that the word desert is added here, because at that time the ancient Gaza was actually desert, having been destroyed by Alexander, and μενουσα ερημος, remaining desert, as Strabo, lib. xvi. p. 1102, says; and that the angel mentioned this desert Gaza to distinguish it from another city of the same name, in the tribe of Ephraim, not far from the place where Philip now was. On this we may observe that, although Gaza was desolated by Alexander the Great, as were several other cities, yet it was afterwards rebuilt by Gabinius. See Josephus, Ant. lib. xv. cap. 5, sect. 3. And writers of the first century represent it as being flourishing and populous in their times. See Wetstein.

Schoettgen thinks that ερημος, desert, should be referred, not to Gaza, but to ὁδος, the way; and that it signifies a road that was less frequented. If there were two roads to Gaza from Jerusalem, as some have imagined, (see Rosenmuller), the eunuch might have chosen that which was desert, or less frequented, for the sake of privacy in his journeying religious exercises.

The angel.

Acts 5:19 But the angel of the Lord by night opened the prison doors, and brought them forth, and said,

Acts 10:7,22 And when the angel which spoke to Cornelius was departed, he called two of his household servants...

Acts 12:8-11,23 And the angel said to him, Gird yourself, and bind on your sandals. And so he did. And he said to him, Cast your garment about you...

Acts 27:23 For there stood by me this night the angel of God, whose I am, and whom I serve,

2 Kings 1:3 But the angel of the LORD said to Elijah the Tishbite, Arise, go up to meet the messengers of the king of Samaria, and say to them...

Hebrews 1:14 Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?

Arise.

1 Chronicles 22:16 Of the gold, the silver, and the brass, and the iron, there is no number. Arise therefore, and be doing, and the LORD be with you.

Isaiah 60:1 Arise, shine; for your light is come, and the glory of the LORD is risen on you.

*etc:

Gaza.

Joshua 13:3 From Sihor, which is before Egypt, even to the borders of Ekron northward, which is counted to the Canaanite...

Joshua 15:47 Ashdod with her towns and her villages, Gaza with her towns and her villages, to the river of Egypt, and the great sea...

Zechariah 9:5 Ashkelon shall see it, and fear; Gaza also shall see it, and be very sorrowful, and Ekron; for her expectation shall be ashamed...

desert. It is probable, that we should refer [eremos,] desert, not to Gaza, but to [hodos,] the way; though Gaza was situated at the entrance of the desert, and the ancient city was in ruins, being destroyed by Alexander.

Matthew 3:1-3 In those days came John the Baptist, preaching in the wilderness of Judaea...

Luke 3:2-4 Annas and Caiaphas being the high priests, the word of God came to John the son of Zacharias in the wilderness...

A Meeting in the Desert
'And the angel of the Lord spake unto Philip, saying, Arise, and go toward the south unto the way that goeth down from Jerusalem unto Gaza, which is desert. 27. And he arose and went: and, behold, a man of Ethiopia, an eunuch of great authority under Candace queen of the Ethiopians, who had the charge of all her treasure, and had come to Jerusalem for to worship, 28. Was returning, and sitting in his chariot, read Esaias the prophet. 29. Then the Spirit said unto Philip, Go near, and join thyself …
Alexander Maclaren—Expositions of Holy Scripture: The Acts

Whether the Imposition of the Priest's Hands is Necessary for this Sacrament?
Objection 1: It would seem that the imposition of the priest's hands is necessary for this sacrament. For it is written (Mk. 16:18): "They shall lay hands upon the sick, and they shall recover." Now sinners are sick spiritually, and obtain recovery through this sacrament. Therefore an imposition of hands should be made in this sacrament. Objection 2: Further, in this sacrament man regains the Holy Ghost Whom he had lost, wherefore it is said in the person of the penitent (Ps. 1:14): "Restore unto …
Saint Thomas Aquinas—Summa Theologica

Whether Penance is a Sacrament?
Objection 1: It would seem that Penance is not a sacrament. For Gregory [*Cf. Isidore, Etym. vi, ch. 19] says: "The sacraments are Baptism, Chrism, and the Body and Blood of Christ; which are called sacraments because under the veil of corporeal things the Divine power works out salvation in a hidden manner." But this does not happen in Penance, because therein corporeal things are not employed that, under them, the power of God may work our salvation. Therefore Penance is not a sacrament. Objection …
Saint Thomas Aquinas—Summa Theologica