Sealing the stone - The sepulchre was made sure by affixing the large stone to the entrance in such a way that it could not be removed without detection. It was sealed. In what way this was done cannot now be certainly told. The cave in which Daniel was cast was fastened in the same manner, and sealed with the king's signet Daniel 6:17, perhaps by fastening the stone in its place with cords, and bringing them together and uniting them with wax, and impressing on that the seal of the king. In this way, letters and books were anciently sealed. Possibly on the sepulchre of Jesus was impressed in this manner the seal of Pilate - the seal of office - making it doubly sure; or it may be that the stone was fitted into the tomb with clay or cement, and on that was impressed the seal of Pilate.
Setting a watch - That is, as large a number of soldiers as they judged necessary to secure the tomb.
We cannot but be struck with the wisdom of God in ordering the circumstances of the Saviour's burial in such a manner as to avoid the possibility of deception. Had all this been done by his "friends," it might have been said that they only pretended to secure the tomb, and only pretended that he was dead. But he was adjudged to be dead "by the Jews themselves;" Pilate was satisfied that that was the fact; they had their own way about his burial; he was buried alone; the place of his sepulchre was made sure, "expressly to prevent his being removed;" and they placed around him a guard, in their own judgment large enough to prevent his being taken away by force or strength. His very enemies, therefore, took every possible precaution to place his resurrection beyond the possibility of suspicion of fraud and imposture, and those precautions were the very means of furnishing the most striking proof that his death, burial, and resurrection were not impositions, but most affecting, awful, and yet cheering realities.

Made the sepulchre sure, sealing the stone, and setting a watch - Or rather, made the tomb secure by the guard, and by sealing the stone. I follow Kypke, in construing μετα της κουστωδιας, with ησφαλισαντο. The guard was to take care that the disciples should not steal him away; and the seal, which was probably the seal of the governor, was to prevent the guards from being corrupted so as to permit the theft. So every thing was done which human policy and prudence could, to prevent a resurrection, which these very precautions had the most direct tendency to authenticate and establish. How wonderful are the wisdom and goodness of God! - and how true is it, that there is neither might nor counsel against him!
1. The death of Christ was ordered, so as to be witnessed by thousands; and if his resurrection take place, it must be demonstrated; and it cannot take place without being incontestable, such are the precautions used here to prevent all imposture.
2. The more the circumstances of the death of Christ are examined, the more astonishing the whole will appear. The death is uncommon - the person uncommon - and the object uncommon; and the whole is grand, majestic, and awful. Nature itself is thrown into unusual action, and by means and causes wholly supernatural. In every part, the finger of God most evidently appears.
3. How glorious does Christ appear in his death! Were it not for his thirst, his exclamation on the cross, and the piercing of his side, we should have found it difficult to believe that such a person could ever have entered the empire of death; but the divinity and the manhood equally appear, and thus the certainty of the atonement is indubitably established.
4. But who can reflect on the state of the poor disciples, during the whole of the time in which our blessed Lord lay under the empire of death, without sharing their sorrows! When he expired on the cross their expectation was cut off; and when his body was laid in the grave their hopes were buried; and nothing but the resurrection of Christ from the dead could have given a resurrection to their hopes. It is true they had heard him say that he would rise again the third day; but in this it is evident their faith was very imperfect; and the uncertainty, perplexity, anxiety, and distress which they in consequence must have suffered, can neither be described nor imagined. Though we know the glorious result, yet who can help sympathizing with the pious father, the virgin mother, and the disconsolate disciples!

So they went,.... From Pilate's palace, to the garden of Joseph, and to the sepulchre there; which whether more than a sabbath day's journey, or two thousand cubits, may be inquired; and if so, then they broke one of their own traditions, which allowed a person to go no further on a sabbath day; See Gill on Acts 1:12.
And made the sepulchre sure; in the following manner,
sealing the stone; that was rolled to the door of it, it may be with some public seal, with Pilate's, or with the sanhedrim's; as the stone at the mouth of the lions' den, in which Daniel was put, was sealed with the king's signet, and with the signet of his lords, Daniel 6:17, that there might be no change of the sentence upon him, and by which it appeared, that his deliverance was by no human assistance: so the stone at Christ's sepulchre was sealed, that it could not be removed without breaking it; which would show, whether any fraudulent methods were taken to remove the body:
and setting a watch; a guard of soldiers, to observe and prevent any person coming near it; or "with the watch": they made sure the sepulchre with the watch; or sealed the stone, the watch being present; all which was overruled by the providence of God, for the greater confirmation of the truth of Christ's resurrection: by the methods taken, it clearly appears, there could be no fraud in the case; the body was laid in a tomb, where no corpse had ever been before; in a tomb hewed out of a rock, to which there was no access, but at the door; where a great stone was rolled; and this had a seal upon it, and a guard of soldiers about it; and hereby there were more witnesses of Christ's resurrection, than otherwise would have been; as the soldiers, though they were afterwards bribed to tell another story; and even the chief priests and Pharisees were convicted that he was risen, or they would never have taken such a method with the soldiers, as they did.

So they went, and made the sepulchre sure, sealing the stone--which Mark (Mark 16:4) says was "very great."
and setting a watch--to guard it. What more could man do? But while they are trying to prevent the resurrection of the Prince of Life, God makes use of their precautions for His own ends. Their stone-covered, seal-secured sepulchre shall preserve the sleeping dust of the Son of God free from all indignities, in undisturbed, sublime repose; while their watch shall be His guard of honor until the angels shall come to take their place.

Sealing the stone. A cord was stretched across the stone door and sealed at each end with wax. The seal would have to be broken to remove the stone.

They went and secured the sepulchre, sealing the stone, and setting a guard - They set Pilate's signet, or the public seal of the sanhedrim upon a fastening which they had put on the stone. And all this uncommon caution was overruled by the providence of God, to give the strongest proofs of Christ's ensuing resurrection; since there could be no room for the least suspicion of deceit, when it should be found, that his body was raised out of a new tomb, where there was no other corpse, and this tomb hewn out of a rock, the mouth of which was secured by a great stone, under a seal, and a guard of soldiers.