The Passover is the Mass

Where in Scripture do we find the passover becomes the Mass?

Here.

Matthew 26:
16 And from that time he sought opportunity to betray him.
17 Now the first day of the feast of unleavened bread the disciples came to Jesus, saying unto him, Where wilt thou that we prepare for thee to eat the passover?
18 And he said, Go into the city to such a man, and say unto him, The Master saith, My time is at hand; I will keep the passover at thy house with my disciples.

Note that Jesus prepares the disciples for a Passover. But this is what He says during that Passover:
26 And as they were eating, Jesus took bread, and blessed it, and brake it, and gave it to the disciples, and said, Take, eat; this is my body.
27 And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it;
28 For this is my blood of the new testament, which is shed for many for the remission of sins.

That, of course, is a description of the Eucharistic meal.  The very same meal we receive at every Mass.

Jesus prepared the disciples for a Passover. But during that Passover, celebrated the Mass. St. Paul obviously understands this:

1 Corinthians 5:7 Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us: