“It was two days
Before the Passover,
Of Unleavened Bread.”
Ἦν δὲ τὸ πάσχα καὶ τὰ ἄζυμα μετὰ δύο ἡμέρας
There is something similar to this in Matthew, chapter 26:2, and in Luke, chapter 22:1, where there was talk of the Passover in 2 days. There were 3 major annual pilgrimage festivals in Jerusalem, Pentecost, Booths, and Passover, with Passover the most popular. This Passover feast celebrated the Israelite Exodus from Egypt. Therefore, this festival reminded the Jewish people of their escape from a foreign country. Thus, the Roman leaders had a heightened alert with more troops in Jerusalem. Mark indicated that Jesus said to his disciples that it was 2 days (μετὰ δύο ἡμέρας), before the Passover (Ἦν δὲ τὸ πάσχα), the festival of Unleavened Bread (καὶ τὰ ἄζυμα) that lasted a whole week. Passover and Unleavened bread were one festival, not 2 separate ones.