Exodus 12:6 commands killing the Passover lamb on the 14th day — sets the timing for the disciples' Passover preparation.

Exodus 12:18-20 institutes the Feast of Unleavened Bread — the context for the disciples' question on its first day.

Exodus 13:6-8 commands eating unleavened bread and retelling the Exodus — background for the disciples preparing the Passover meal.

Leviticus 23:5-6 links Passover and Unleavened Bread — directly explains the feast day mentioned in Matthew 26:17.

In Leviticus 23:6, the Feast of Unleavened Bread is defined — this is the feast referred to when Matthew mentions the first day of Unleavened Bread.

Numbers 28:16 sets the Passover date on the 14th — this clarifies the timing behind the disciples' question about preparing the Passover.

Numbers 28:17 describes the seven-day feast of Unleavened Bread starting on the 15th — the context for Matthew's 'first day of Unleavened Bread.'

Deuteronomy 16:1-4 commands observing Passover and Unleavened Bread together — the very practice the disciples are following in Matthew.

Mark 14:12 gives the parallel account of the same event — the disciples' question about preparing the Passover on the first day of Unleavened Bread.

Luke 22:7 is the parallel account — it also notes the day of Unleavened Bread when the Passover lamb was sacrificed.

Luke 22:8 records Jesus sending Peter and John to prepare the Passover — the direct response to the disciples' question in Matthew.

In Luke 22:9, the disciples ask the same question, confirming the synoptic parallel of this Passover preparation scene.

1 Corinthians 11:23 recounts the Last Supper on the night of betrayal, directly tying the Passover meal prepared here to the institution of the Eucharist.

Exodus 12:21 gives the original command to prepare the Passover lamb, which the disciples are now carrying out.