My soul is sorrowful. He communicates to them his sorrow, in order to arouse them to sympathy; not that he was unacquainted with their weakness, but in order that they might afterwards be more ashamed of their carelessness. This phrase expresses a deadly wound of grief; as if he had said, that he fainted, or was half-dead, with sorrow. Jonah (4:9) makes use of a similar phrase in replying to the Lord; I am angry even to death. I advert to this, because some of the ancient writers, in handling this passage with a misapplication of ingenuity, philosophize in this way, that the soul of Christ was not sorrowful in death but only even to death. And here again we ought to remember the cause of so great sorrow; for death in itself would not have so grievously tormented the mind of the Son of God, if he had not felt that he had to deal with the judgment of God.

My soul is exceeding sorrowful - His human nature - his soul - was much and deeply affected and pressed down.
Even unto death - This denotes extreme sorrow and agony.
The sufferings of death are the greatest of which we have any knowledge; they are the most feared and dreaded by man; and those sufferings are therefore put for extreme and indescribable anguish. The meaning may be thus expressed: My sorrows are so great that under their burden I am ready to die; such is the anxiety of mind, that I seem to bear the pains of death!
Tarry ye here and watch with me - The word rendered "watch" means, literally, to abstain from sleep; then to be vigilant, or to guard against danger. Here it seems to mean to sympathize with him, to unite with him in seeking divine support, and to prepare themselves for approaching dangers.

Then saith he - Then saith - Jesus: - I have added the word Jesus, ὁ Ιησους, on the authority of a multitude of eminent MSS. See them in Griesbach.
My soul is exceeding sorrowful, (or, is surrounded with exceeding sorrow), even unto death - This latter word explains the two former: My soul is so dissolved in sorrow, my spirit is filled with such agony and anguish, that, if speedy succor be not given to my body, death must be the speedy consequence.
Now, the grand expiatory sacrifice begins to be offered: in this garden Jesus enters fully into the sacerdotal office; and now, on the altar of his immaculate divinity, begins to offer his own body - his own life - a lamb without spot, for the sin of the world. St. Luke observes, Luke 22:43, Luke 22:44, that there appeared unto him an angel from heaven strengthening him; and that, being in an agony, his sweat was like great drops of blood falling to the ground. How exquisite must this anguish have been, when it forced the very blood through the coats of the veins, and enlarged the pores in such a preternatural manner as to cause them to empty it out in large successive drops! In my opinion, the principal part of the redemption price was paid in this unprecedented and indescribable agony.
Bloody sweats are mentioned by many authors; but none was ever such as this - where a person in perfect health, (having never had any predisposing sickness to induce a debility of the system), and in the full vigor of life, about thirty-three years of age, suddenly, through mental pressure, without any fear of death, sweat great drops of blood; and these continued, during his wrestling with God to fall to the ground.
To say that all this was occasioned by the fear he had of the ignominious death which he was about to die confutes itself - for this would not only rob him of his divinity, for which purpose it is brought, but it deprives him of all excellency, and even of manhood itself. The prospect of death could not cause him to suffer thus, when he knew that in less than three days he was to be restored to life, and be brought into an eternity of blessedness. His agony and distress can receive no consistent explication but on this ground - He Suffered, the Just for the Unjust, that he might Bring us to God. O glorious truth! O infinitely meritorious suffering! And O! above all, the eternal love, that caused him to undergo such sufferings for the sake of Sinners!

(10) Then saith he unto them, My soul is exceeding sorrowful, even unto death: tarry ye here, and watch with me.
(10) Christ, a true man, who is about to suffer the punishment which we should have suffered for forsaking God, is forsaken by his own: he has a terrible conflict with the horror and fear of the curse of God: out of which he, since he escaped as a conqueror, causes us not to be afraid of death any more.

Then saith he unto them,.... The three disciples, Peter, James, and John, who, by his looks and gestures, might know somewhat of the inward distress of his mind; yet he choose to express it to them in words, saying,
my soul is exceeding sorrowful, even unto death. That Christ had an human soul, as well as an human body, is clear from hence; and which was possessed of the same passions as ours are, but without sin, such as joy, love, grief, sorrow, &c. and at this time its sorrows were exceeding great: his soul was beset all around with the sins of his people; these took hold on him, and encompassed him, which must, in the most sensible manner, affect his pure and spotless mind; the sorrows of death and hell surrounded him on every side, insomuch that the least degree of comfort was not let in to him; nor was there any way open for it, so that his soul was overwhelmed with sorrow; his heart was ready to break; he was brought even, as it were, to the dust of death; nor would his sorrows leave him, he was persuaded, until soul and body were separated from each other; see a like phrase in Judges 16:16,
tarry ye here. The Ethiopic adds, "till I shall return", for he was going a little further from them, to vent his grief, and pour out his soul unto God. Munster's Hebrew Gospel reads it, "expect me", or "wait for me here", signifying, that he should return to them shortly,
and watch with me. It was night, and they might be heavy and inclined to sleep: he knew it would be an hour of temptation both to him and them, and therefore advises them to watch against it; and to observe how it would go with him, and what should befall him, that they might be witnesses of it, and be able to testify what agonies he endured, what grace he exercised, and how submissive he was to his Father's will.

My soul is exceedingly sorrowful, even unto death. The weight of woe was literally crushing out the Savior's life.
Tarry ye here, and watch. He had wished his chosen disciples to be near him in his woe; and yet, as it advanced, he felt that he must retire even from them, and be alone with himself and his Father.