Each of the Gospels tells the story of the Resurrection in a slightly different way. They shape it from a point of view. There's a case for saying Matthew's point of view, in chapter 28, is doubt, uncertainty and incompleteness.
First, it's the women who were the first witnesses to the empty tomb. All the gospels agree on that, but for Matthew they are the main witnesses; the male disciples appear right at the end. In 1st century Palestine, women were second class citizens, not taken seriously. As the 18th century Lord Chesterfield said: "A man of sense only trifles with women, plays with them, humours and flatters them, as he does with a sprightly forward child; but he neither consults them about, nor trusts them with serious matters...' Women were not allowed to testify in a Jewish or a Roman court of law. So having women as the witnesses was an invitation to Matthew's readers to disbelieve him if they wished.
Second: the middle part of the chapter is about the plausible story the Jewish leaders put about to explain the empty tomb. The line that the chief priests are going to take with the guards is that the disciples came and stole the body. From our perspective, it is not really all that plausible, because of what happened to those disciples: many of them were martyred, all of them ran terrible risks, all of them suffered. You'll do that for something you really believe, but you won't do it for a lie. However, rather than just ignoring the possibility that that might have happened, Matthew almost advertises it. It's almost as if he's saying, 'If you want a reason not to believe, here's one.'
Third, almost the last words Matthew writes are, 'Then the 11 disciples went to Galilee, to the mountain where Jesus had told them to go. When they saw him, they worshipped him; but some doubted.' Even some of the 11 disciples were not entirely convinced that Jesus was risen. Why would Matthew write that? If even they didn't wholly believe, why should we? The answer is that Matthew was not just presenting a bald, dry narrative of facts: he was writing for us. He presents those disciples as doubters because that's what people do. It is not as though there was a first generation of spiritual superheroes who knew the truth because they'd seen it with their own eyes, and everyone else has to stumble along in their wake. Being a Christian is now, and has always been, about faith, trust and hope.
In the long run, we don't do ourselves any favours by pretending that Christianity is easy, or sensible, or obvious. If we are Christians, we are going against the stream of how the world works. That's not easy, and Matthew says it never has been.
However: ultimately, this chapter is profoundly encouraging. Matthew is looking over the precipice, into doubt and uncertainty, knowing that we will all look over it at one time or another. But he finishes with Jesus saying: 'All authority is given to me; go and make disciples; I am with you always.'
