Jesus remained on the cross for three hours before He died "at the ninth hour" (Mark 15:34; see Matthew 27:46). Since they were using the Hebrew method of counting the hours of the day from sunrise, the gospel writers indicate that Jesus was crucified around noon and died about 3 PM. They are remarkably unanimous on this point.
Richard T. Ritenbaugh
'After Three Days'
Christ's sacrifice confirming the New Covenant occurred on the anniversary of God's covenantal promise to Abraham—the same day and hour! Its specific timing draws our attention to the “eternal inheritance” promised to Abraham and his spiritual seed. Jesus set the example of when and how He wants us to observe the Passover—at the beginning of the 14th—and then on that afternoon, He shed His blood so that a New Covenant could be made.
This covenant is an outgrowth of the covenant with Abraham, making his “great nation” a reality. It provides for justification on the basis of faith—for Israelite and Gentile alike—and promises eternal life to those who continue to the end in faith. Christ is our Passover, not by lining up with the timing outlined in the instructions given to Israel, but by renewing and advancing the covenant God made with Abraham.
David C. Grabbe
Why Was Jesus Not Crucified as Passover Began? (Part Two)