“While they were eating,

Jesus took

A loaf of bread.

After blessing it,

He broke it.

He gave it

To them.

He said.

‘Take!

This is my body.’”

Καὶ ἐσθιόντων αὐτῶν λαβὼν ἄρτον εὐλογήσας ἔκλασεν καὶ ἔδωκεν αὐτοῖς καὶ εἶπεν Λάβετε· τοῦτό ἐστιν τὸ σῶμά μου.

This is almost word for word in Mathew, chapter 26:26, but in Luke, chapter 22:19, it has a little more elaboration.  Paul used almost the same wording in I Corinthians, chapter 11:23-24.  In John, chapter 6:35-58, Jesus was preaching about eating the flesh of the Son of Man, the bread of life, so that he does not have a Last Supper institution narrative.  Mark said that while they were eating (Καὶ ἐσθιόντων αὐτῶν) the Passover meal, Jesus took a loaf of bread (λαβὼν ἄρτον).  He spoke the blessing or blessed it (εὐλογήσας).  He broke it into pieces (ἔκλασεν).  Then he gave it to them (καὶ ἔδωκεν αὐτοῖς).  He said (καὶ εἶπεν) that they should take (Λάβετε) this bread, because it was his body (τοῦτό ἐστιν τὸ σῶμά μου).  There was no mention of eating it here, as in Matthew.  This Eucharistic institution narrative may already have been in this stylized form at the time of the writing of this gospel.  There was no specific indication whether this was leavened or unleavened bread, just a loaf of bread.  However, if it was a Passover meal on the feast of the Unleavened Bread, the evident assumption would be that it was unleavened or “matzah” bread.  Clearly, this institution narrative has had a profound effect on further Christian Eucharistic sacramental theological development.