Sitting
Entering the tomb, they saw a young man sitting at the right, wearing a white robe; and they were amazed.
Mark 16:5 NASB
11 But Mary was standing outside the tomb weeping; and so, as she wept, she stooped and looked into the tomb;
12 and she saw two angels in white sitting, one at the head and one at the feet, where the body of Jesus had been lying.
John 20:11-12 NASB
Standing
3 but when they entered, they did not find the body of the Lord Jesus.
4 While they were perplexed about this, behold, two men suddenly stood near them in dazzling clothing;
Luke 24:3-4 NASB
Question
Were the angels sitting or standing inside the grave? It looks like the question: Was Peter sitting or standing at the fire when he repudiated Jesus. It would be easy in both cases to conclude that they were first standing as they entered the grave and then they sat down just as Peter, before he sat at the fire, had to approach it. Although there is no better answer, let’s examine the facts.
Right order
The Gospels tells the resurrection story in brief glimpses and it is only necessary to put everything in the right order. Let’s begin with the women who, as everybody knows, went to the grave early that morning. They discovered the stone had been rolled away and one of them, Mary Magdalene, went to tell the disciples, leaving the other women at the garden (John 20:2). Then Peter and John went to look at the tomb for themselves. They entered the tomb, didn’t find the body and departed (John 20:3-10). Then the women came on the scene.
The women and the angels
1. Luke 24:3 … when they entered, they did not find the body of the Lord Jesus.
The first thing they did was inspect the tomb for themselves. But then?
The next verse (4) begins in Greek with the word Kai (And), unfortunately not translated here. The beginning of a sentence with “And” always refers to interruption in the course of events:
2. Luke 24:4 [And] while they were perplexed about this, behold, two men suddenly stood near them in dazzling clothing;
This was outside the tomb as from Matthew 28:1-5 we know that the leading angle who had rolled the stone away, addressed the women outside the grave as he invited them to look into the tomb (28:6): “Come, see the place where He was lying.” Of course these angels were standing outside.
3. Mark 16:5 Entering the tomb, they saw a young man sitting at the right, wearing a white robe; and they were amazed.
When the women entered the tomb for the second time they had been following the angels who had invited them to come and see. So when they came in they saw that the angels had positioned themselves (sitting inside) at the head and at the feet of the place where Jesus had laid. There is only mention of one angel; this is speaker-reduction (i.e. mentioning only the individual whose words are presented in the narrative Mark 16:6-7).
It is well known that Mary Magdalene left the grave and met Jesus whom she didn’t recognize immediately. But outside, before she met Jesus, she turned to look back inside the grave, probably to see whether the other women had followed her, but her attention was drawn again to the white angels sitting inside near the place where Jesus’ body had been. They were surprised that she was still weeping after the inspection of the place where the body had been lying.
4. John 20:11-12 11 But Mary was standing outside the tomb weeping; and so, as she wept, she stooped and looked into the tomb;
12 and she saw two angels in white sitting, one at the head and one at the feet, where the body of Jesus had been lying.
13 And they *said to her, “Woman, why are you weeping?”
Conclusion
The sitting and standing of the angels has been properly explained within the story of Jesus’ resurrection and so the conclusion is justified:
No Bible Contradiction
Additional: the place where they laid Him
1. The angels wanted the women to look carefully to the place where Jesus had been lain. Why? Because of the miracle they could see there. Jesus’ body was wrapped in a linen shroud, but the wrapped shroud was empty and still in the form of the burial they had been witnessed. The view of this compelled the women to conclude that Jesus had been resurrected through the linen shroud. It was a visible remnant of the resurrection miracle, as He entered closed rooms in his resurrected state (John 20:26). This is why the place where they had laid Him plays such a prominent part in the resurrection message of the Gospels. The kernel of the matter is not only the empty tomb, but also the empty shroud!
2. It is generaly accepted that the angels accompanied Jesus when after the resurrection He went outside the tomb and walked further into the garden to say his morning prayers as He was accustomed. There were no human whitnesses of this as the soldiers had fled and the women had not yet arrived. However, when the women were in great distress after their inspection of the tomb the angels were sent by the Lord to comfort them.
3. See also the article: Were men or angels inside or outside the tomb when the women arrived?