This passage is an example of bringing the past into the present. The technical term for this is ‘anamnesis’.
Here the people of Israel are asked to remember the covenant made between them and God on Mount Sinai. This is where God gave the people the Ten Commandments to follow, and promised to look after them so long as they were obedient.
Moses appears to be talking to the people forty years after the original event that he's recalling. Like himself, a very few of the older members of the community might actually have been there as participating adults. Some of them would have been there to witness it as children. Many would not have been born.
But Moses would not have sympathised with the argument, put forward by the Brexiteers, that important national commitments have to be re-examined every so often. For him this past event must be continually brought into the present and made binding on each new generation.
'You must be careful not to forget the things you have seen God do for for you,’ says Moses. Many of the people have not seen the original event, but they have heard the story recited and perhaps re-enacted, and brought from the past into the present so that they too become witnesses of what happened. 'Keep reminding yourselves, and tell your children and grandchildren as well.’ This is ‘anamnesis’ in action, making the past real and relevant now.
There were other moments of anamnesis in Jewish worship, most especially The Passover meal. Someone has said that the Jewish faith is not so much about understanding what God is like but about remembering how God has encountered human beings in the past, and chosen to relate to our ancestors, and then identifying ourselves with those past experiences and bringing them into the present.
The Mishnah, an ancient Jewish oral tradition which interpreted scripture for new generations, says, ‘In every generation we must view ourselves as if we came out of Egypt… It was not only our ancestors that the Holy One redeemed, but us, too, with them.’
And this same process of anamnesis applies to Holy Communion, when we bring Jesus’s last supper, and the effectiveness of his death and resurrection, into the present. 'Do this in remembrance of me,’ is more than just reminding ourselves about something that happened long ago. It is about bringing its power and effectiveness into the present.
When Jesus says, 'Do this to remember me,’ he means 're-enact this breaking and sharing to bring my power and presence into the here and now to strengthen and encourage you.