There’s a huge difference between saying that Jesus resurrected “on the third day” versus saying “after three days”. Some people would often interchange these phrases but the latter is incorrect.
Since Jesus died on a Friday, saying that he raised from the dead after three days would mean that he resurrected on a Monday. This goes against what is written in scripture which clearly states he resurrected on Sunday.
So how do we count the days from Good Friday to Easter Sunday as three days?
It’s simple. The answer is: Friday was the first day, and then Saturday was the second day, and finally Sunday was the THIRD day. Jesus died on the first day and raised on the third.
Understanding Passover days
Scripture counts the days from Christ’s death to his resurrection in ordinal format (Ex: 1st, 2nd, 3rd, 4th, 5th…), because what’s being counted here are the Passover days. Passover is actually a 7-day Jewish holiday. It starts on the 15th day of the first month of the Hebrew calendar which is called Nisan. So it occurs on Nisan 15 and ends on Nisan 21.
Scripture shows that Jesus was crucified and died on the first day of the Passover, which is Nisan 15. This would mean he resurrected on the third day of the Passover, Nisan 17.
For more reference on the Passover ritual prescribed by God, see Exodus 12.
But didn’t Jesus and his disciples celebrated Passover on a Thursday (Nisan 14)?
One very important detail to take note of is that Jesus and his disciples celebrated it “in the night” of Thursday as Paul stated in 1 Corinthians 11:23–25. Because in the old times, the night is already an anticipation of the next day. So what happened on the night of Nisan 14(Thurs) also coincides with Nisan 15(Fri).
Starting the celebration on Thursday night would makes sense because that is also what is prescribed by God in the Old Testament. Exodus 12: 6 says:
6You will keep it until the fourteenth day of this month, and then, with the whole community of Israel assembled, it will be slaughtered during the evening twilight.
This verse instructs that the lamb prepared for the Passover is to be kept until the 14th day of Nisan. But then, only then, on the night of that day shall it be slaughtered for an offering.
Our “lamb” is Jesus and on the night of the 14th day of Nisan, he was “slaughtered” so that we may consume his flesh and blood on that very same night as also prescribed in Exodus 12:8:
8They will consume its meat that same night, eating it roasted with unleavened bread and bitter herbs.
The sacrifice of Jesus on that night makes his death on the cross on Friday afternoon one in the same. His “slaughter” or sacrifice on Thursday night is his act of offering his body and blood to us as food and drink. He was “slaughtered” by means that our spiritual death was placed upon him when we became one with him in this new covenant. It’s like, when a man and a woman marries and the woman had debt prior to the marriage, the man would now also have a share in paying that debt. But instead of paying just a portion of our debt, Jesus paid for everything!
To put it in simpler summary or perspective: Thursday night extends to Friday night.