For I received from the Lord what I also handed on to you, that the Lord Jesus, on the night he was handed over, took bread,
and, after he had given thanks, broke it and said, “This is my body that is for you. Do this in remembrance of me."
1 Corinthians 11:23-24

"On the day we call the day of the sun, all who dwell in the city or country gather in the same place. 

The memoirs of the apostles and the writings of the prophets are read, as much as time permits. 

When the reader has finished, he who presides over those gathered admonishes and challenges them to imitate these beautiful things.

Then we all rise together and offer prayers for ourselves . . .and for all others, wherever they may be, so that we may be found righteous by our life and actions, and faithful to the commandments, so as to obtain eternal salvation. 

When the prayers are concluded we exchange the kiss. 

Then someone brings bread and a cup of water and wine mixed together to him who presides over the brethren. 

He takes them and offers praise and glory to the Father of the universe, through the name of the Son and of the Holy Spirit and for a considerable time he gives thanks that we have been judged worthy of these gifts. 

When he has concluded the prayers and thanksgivings, all present give voice to an acclamation by saying: 'Amen.' 

When he who presides has given thanks and the people have responded, those whom we call deacons give to those present the 'eucharisted'
bread, wine and water and take them to those who are absent."

St. Justin Martyr's description of the Holy Mass, as it was celebrated only 100 years following the Crucifixion and Resurrection of Our Lord, highlights the centrality of worship among Christians going back to the Apostles.  Reading it closely we see each part of the Mass we celebrate today anticipated by our earliest brothers and sisters in the Catholic faith.  

But the Mass is not only an event that occurs in the "here and now".  The Mass on earth is an unveiling of the Eternal Mass taking place in Heaven at one and the same "moment".  The Apostle John gave us a peek at this perpetual event:

Day and night they do not stop exclaiming:

“Holy, holy, holy is the Lord God almighty,

who was, and who is, and who is to come.”

Then I saw standing in the midst of the throne and the four living creatures and the elders a Lamb that seemed to have been slain.

When he took [the scroll], the four living creatures and the twenty-four elders
fell down before the Lamb.

They sang a new hymn:

“Worthy are you to receive the scroll

and to break open its seals,

for you were slain and with your blood you purchased for God

those from every tribe and tongue, people and nation."

(Revelation 4:8, 5:6, 8-9)