The bloody sweat
Whether the angel and the sweat belong to Luke or were added from tradition.
Luke 22:43-44
43An angel from heaven appeared to him, strengthening him.
44Being in agony he prayed more earnestly. His sweat became like great drops of blood falling down on the ground.
What each tradition says
Rabbinic / Midrashic
No sourced position found. Checked the Jewish Encyclopedia (1905): arts. "Son of God" (13912), "Trinity" (14519), "Christianity in Its Relation to Judaism" (4366) and searches on the passion narrative - no treatment of Luke xxii. 43-44 found; Sefaria (whose corpus contains no Gospel commentary) likewise has none.
Patristic
Hilary notes that many Latin and Greek manuscripts say nothing of the angel's coming or the bloody sweat. He suspends judgment whether this is an omission where absent or an interpolation where present, since the copies disagree. He warns heretics not to take this as confirming his weakness or need for an angel's help and comfort.
Hilary of Poitiers, On the Trinity (NPNF2-09) — Book X, § 41 - the angel and the bloody sweat in the manuscripts
Catholic
Haydock states that an angel strengthened Christ, who was truly God and truly man. Because of the real union of his divine person and nature with our weak and infirm human nature, Christ took on our infirmities, sin excepted.
George Leo Haydock, George Haydock's Catholic Bible Commentary (1859) — Comment on Luke xxii. 43
Orthodox
Theophylact states that the preceding prayer was of His human nature, not His divine, as the Arians say. He says this is argued from what is said of His sweat: His sweat was as it were great drops of blood falling down to the ground.
Theophylact of Ohrid, Catena Aurea: Commentary on the Gospels, Vol. 5, St. Luke, Part 2 (J. H. Newman trans.) — On Luke xxii. 43-44 (gloss attributed to "Theophyl.")
Reformed / Protestant
Gill holds the passage was expunged, perhaps by orthodox persons who thought it favored the Arians, or rather by Armenians or Aphthartodocetae who asserted Christ's human nature was incorruptible. Yet he says it is in the most ancient and approved copies and in all the Oriental versions, and therefore is to be retained.
John Gill, John Gill's Exposition of the Whole Bible — Exposition of Luke xxii. 44 (the bloody sweat in the copies)
Evangelical
Wesley says Jesus was probably grappling with the powers of darkness, feeling God's wrath while devils used force and malice to persecute and distract his spirit. He prayed more earnestly, with stronger cries and tears. His sweat was as it were great drops of blood, forced out by vehement distress and falling to the ground.
John Wesley, John Wesley's Notes on the Bible, Notes on the Gospel According to St. Luke — Note on Luke xxii. 44 (in the note on v. 43-44)