The interpretation timeline
Luke 9:7 Douay-Rheims

Now Herod, the tetrarch, heard of all things that were done by him; and he was in a doubt, because it was said

A.D. 407 – 1871 5 witnesses 9 excerpts

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“(Hom. 48. in Matt.) It was not till a long time had passed that Herod took notice of the things that were done by Jesus, (to shew you the pride of a tyrant,) for he did not acknowledge them at first, as it is said, Now Herod heard, &c.”
“For sinners fear both when they know, and when they are ignorant; they are afraid of shadows, are suspicious about every thing, and are alarmed at the slightest noise. Such in truth is sin; when no one blames or finds fault, it betrays a man, when no one accuses it condemns, and makes the offender timid and backward. But the cause of fear is stated afterwards, in the words, Because that it was said of some.”
Source
“(ubi sup.) When Herod then heard of the miracles which Jesus was performing, he says, John have I beheaded, which was not an expression of boasting, but by way of allaying his fears, and bringing his distracted soul to recollect that he had killed. And because he had beheaded John, he adds, but who is this.”

Scholastic

c. 1100 – 1500
1107
A.D.
c. 1055–1107
“Herod was the son of Herod the Great who slew the children, who was king, but this Herod was tetrarch. He inquired about Christ, who He was. Hence it follows, And he was perplexed.”
“For the Jews expected a resurrection of the dead to a fleshly life, eating and drinking, but those that rise again will not be concerned with the deeds of the flesh.”
“If John is alive and has risen from the dead, I shall know him when I see him; as it follows, And he sought to see him.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Now Herod the tetrarch,.... Of Galilee, and who is called a king in Mar 6:14 as he is here in the Ethiopic version: heard of all that was done by him; of all the miracles that were wrought by Christ, and his apostles; the fame of which were the more spread through the mission of the apostles, and the journey they took through all the towns and cities of Galilee, which were in Herod's jurisdiction; by which means he, and his court, came to the knowledge of them, the whole country, ringing with the account of the same: and he was perplexed; anxious, and distressed, not knowing well what to think of Christ, and the different sentiments of men about him: be was afraid lest he should be John the Baptist risen from the dead, whom he had beheaded: he hesitated about it at first, though he afterwards was fully persuaded, in his own mind, that it was he, as some affirmed; and this gave him great uneasiness, and filled him with distress and horror: because that it was said of some that John was risen from the dead; and he began to fear it was true, though willing to disbelieve it, at least to make a question of it, especially in public; though in private, to his own family and servants, he was free to tell his mind.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Herod the tetrarch - See on Mat 2:1 (note); Mat 14:1 (note). By him - This is omitted by BCDL, two others, the Coptic, Sahidic, Armenian, and four of the Itala. It is probable that Luke might have written, Herod, hearing of all the things that were done, etc.; but Matthew says particularly, that it was the fame of Jesus of which he heard: Mat 14:1. He was perplexed; - He was greatly perplexed διηπορει· from δια emphat. and απορεω, I am in perplexity. It is a metaphor taken from a traveler, who in his journey meets with several paths, one only of which leads to the place whither he would go; and, not knowing which to take, he is distressed with perplexity and doubt. The verb comes from α, negative, and πορος, a way or passage. A guilty conscience is a continual pest: - Herod had murdered John, and he is terribly afraid, lest he should arise from the dead, and bring his deeds to light, and expose him to that punishment which he deserved. See Mar 6:16.”
Source
1871
A.D.
1871
“HEROD TROUBLED AT WHAT HE HEARS OF CHRIST DESIRES TO SEE HIM. (Luk 9:7-9) perplexed--at a loss, embarrassed. said of some, that John was risen--Among many opinions, this was the one which Herod himself adopted, for the reason, no doubt, mentioned on Mar 6:14.”
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.