The covenants of Abraham and Moses were fulfilled in our redemption though Jesus Christ. Those days are fulfilled once more in the middle of the seven years of Tribulation. The Tribulation begins on the 10th of Tishri or the Day of Atonement, so the middle of the tribulation is the 10th of Nisan. On the 10th, the lamb was chosen for Passover so the Antichrist will begin his reign over the world. The two witnesses will be killed on the 14th of Nisan or Passover and resurrect on the 18th of Nisan or Firstfruits.

When they [two witnesses] shall have finished their testimony, the beast that ascends out of the bottomless pit shall make war against them, and shall overcome them, and kill them. And after three days and a half the spirit of life from God entered into them, and they stood upon their feet; and great fear fell upon them which saw them (Revelation 11:7, 11).

Through the Abrahamic covenant, the exodus out of Egypt and the New Covenant in Jesus Christ, we see God's plan fulfilled in God's time. Redemption is completed in Trumpets with His return for His people, Atonement with His return to earth and Tabernacles with His reign on earth. The pattern of God's time helps us understand God's plan for the past and the future.

References: 21st Century Revelation: World Wars, Iraq Wars & End Wars Chapters 13 - Minor Feast, Major Events, Chapter 16 - The Life of Christ, Chapter 17 - Basic Bible Chronology

Each spring, we celebrate the death, burial and resurrection of Jesus Christ. By faith in His sacrifice, we are forgiven of our sin and receive the free gift of salvation. These holy days are floating holidays on the Roman calendar that link to the Passover full moon on the Jewish calendar. When we talk about prophecy, we say we do not know the time. However before the world was created, our sovereign God had a specific plan with a specific time. God revealed that plan though His Word. See Jewish Calendar.

Behold, the former things are come to pass, and new things do I declare: before they spring forth I tell you of them (Isaiah 42:9).

In the fourteenth day of the first month at even is the Lord's passover. And on the fifteenth day of the same month is the feast of unleavened bread unto the Lord: seven days you must eat unleavened bread. In the first day you shall have an holy convocation: you shall do no work therein. But you shall offer an offering made by fire unto the Lord seven days: in the seventh day is an holy convocation: you shall do no work therein (Leviticus 23:5-7, 8).

On the 15th of Nisan 2023 AM (years from creation), God made a covenant with Abraham and his decedents. On the 15th of Nisan 2453 AM or the first day of Unleavened Bread, the children of Israel left Egypt. They were not slaves in Egypt for 430 years. There were 215 years from the Abrahamic covenant until Jacob moved to Egypt. They lived freely in Egypt for 95 years and slaves for about 120 years. So there were 430 years from the Abrahamic covenant to the Mosaic covenant.

It came to pass at the end of the four hundred and thirty years, even the same day it came to pass, that all the hosts of the Lord went out from the land of Egypt (Exodus 12:41)

The blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith. And this I say, that the covenant, that was confirmed before of God in Christ, the Law, which was four hundred and thirty years after [the Abrahamic covenant], cannot disannul, that it should make the promise of none effect (Galatians 3:14, 17).

On the 15th of Nisan 4000 AM on the Feast of Unleavened Bread, Jesus Christ was in the grave. Jesus Christ was crucified on Passover, he was buried by Unleavened Bread and rose again on Firstfruits. The Abrahamic covenant, the exodus from Egypt and redemption were on the same day on the Jewish calendar. God told Abraham and Moses the day of redemption. See Jewish Calendar.

Now is Christ risen from the dead, and become the firstfruits of them that slept. For as in Adam all die, even so in Christ shall all be made alive (1 Corinthians 15:20-22).