In Paul's first letter to Corinth he writes to them about their sloppy during the annual Passover meal. This passage shows us that the newly formed christian churches continued to keep the annual passover observance with new symbols and spiritual meaning.

In this section of the bible Paul stresses the importance of this annual Passover observance for Christians by reminding the Corinthians that this was a teaching he had received directly from Jesus Christ. Paul also reminds the Corinthians that they are observing the Passover on the same night that Jesus did (which was the 14th day of the first month of God's calendar).

I Corinthians 11:20-34

 Therefore when you come together in one place, it is not to eat the Lord's Supper.  For in eating, each one takes his own supper ahead of others; and one is hungry and another is drunk.   What! Do you not have houses to eat and drink in? Or do you despise the church of God and shame those who have nothing? What shall I say to you? Shall I praise you in this? I do not praise you.  For I received from the Lord that which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread;   and when He had given thanks, He broke it and said, "Take, eat; this is My body which is broken for you; do this in remembrance of Me.''   In the same manner He also took the cup after supper, saying, "This cup is the new covenant in My blood. This do, as often as you drink it, in remembrance of Me.''   For as often as you eat this bread and drink this cup, you proclaim the Lord's death till He comes.  Therefore whoever eats this bread or drinks this cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord.   But let a man examine himself, and so let him eat of that bread and drink of that cup.   For he who eats and drinks in an unworthy manner eats and drinks judgment to himself, not discerning the Lord's body.  For this reason many are weak and sick among you, and many sleep.   For if we would judge ourselves, we would not be judged.  But when we are judged, we are chastened by the Lord, that we may not be condemned with the world. Therefore, my brethren, when you come together to eat, wait for one another. But if anyone is hungry, let him eat at home, lest you come together for judgment. And the rest I will set in order when I come.

I Corinthians 6:19-2

Paul also connects the sacrificial death of Jesus with the annual Passover observance here: 

Your glorying is not good. Do you not know that a little leaven leavens the whole lump? Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover, was sacrificed for us. Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.