I thought that was an interesting question…  So here was the answer I gave (with a few more Bible verses than I originally offered off the top of my head!!). I think there are at least two reasons why it was the third day rather than any other day:

1) A symbolic reason. “The third day” is a symbolically significant day throughout Scripture. It’s the day the Earth gave forth its fruit at creation (Genesis 1:12); the day Abraham tried to sacrifice Isaac and yet returned with him alive (Genesis 22:4ff); the day Pharaoh’s cup bearer and Joseph’s brothers were released from prison (Genesis 42:17-18); the day God descended at Sinai with thunder and lightning and a new covenant (Exodus 19:16ff); when the Israelites crossed the Jordan to possess the Promised Land (Joshua 1:11; 3:2); when various famines came to an end (2 Sam 21:1; 1 Kings 18:1); when Jonah was freed from the belly of the fish (Jonah 1:17; 2:10). And so on…

The third day is a day of change. A day of breakthrough. It’s a day when God intervenes for His people and their circumstances are radically transformed. It’s a day laden with symbolic potential, all of which is beautifully present and fulfilled in the resurrection of Jesus. He came forth from the ground, the true sacrifice returned alive, set free from imprisonment, establishing a new covenant and opening the way to the Promised land, bringing an end to an era of misery, as he walked free from the belly of the earth.

Symbolically speaking, the resurrection could hardly have happened on any other day!

2) A prophetic reason. The third day is not only a symbolic or literary device, however. Scripture describes Jesus’ third day resurrection as being the direct fulfilment of prophecy. ‘He was buried and he was raised on the third day according to the Scriptures’ (1 Corinthians 15:4).

It’s likely that Paul was speaking about the whole sweep and pattern of Scripture rather than one specific verse, and he may have had in mind some of the verses cited above. We know that Jesus applied Jonah’s three day experience to himself: “For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth” (Matthew 12:40) and Paul may have done likewise.

But it’s likely that Paul also has in mind specific prophetic passages, such as:

“Come, let us return to the Lord; for he has torn us, that he may heal us; he has struck us down, and he will bind us up. After two days he will revive us; on the third day he will raise us up, that we may live before him” (Hosea 6:1-2).

In one sense Hosea 6 would have been read as a general statement of trust in God: “Let us return to the Lord, because He is the one who heals and restores. He always has done. He always will. And typically He does such things on the third day!” But it’s actually likely that Hosea 6 was originally read as a vain hope rather than a statement of expectation. See God’s response in verses 4 onwards. Whenever God would extend his healing and mercy to Israel they continued in wickedness (7:1ff). Israel was longing for a third day restoration, but they weren’t going to get it, because of their consistent unfaithfulness.

But the language of healing, revival, being raised up and living in His presence is tantalisingly apt to describe Jesus’ resurrection. As the embodiment of Israel – the faithful embodiment of Israel; who never ‘transgressed the covenant’ (6:7) as the first Adam did – Jesus experienced the third-day restorative power of God.

I think that Paul was referring to prophecies like this, and that Hosea 6 was also in Jesus’ own mind as he predicted his death and his third-day resurrection (Matt 16:21; 17:23; 20:19; Mark 9:31; 10:34; Luke 24:6-8; John 2:19). It is unlikely that in 1 Corinthians 15, Paul was thinking of Jesus’ prophecies, since they weren’t Scripture at that point in time. But these prophecies of Jesus were so well known in his day that the Chief Priests and Pharisees went to Pilate and said, “Sir, we remember that while he was still alive that deceiver said, ‘After three days I will rise again.’ So give the order for the tomb to be made secure until the third day. Otherwise, his disciples may come and steal the body and tell the people that he has been raised from the dead. This last deception will be worse than the first” (Matt 27:63-64).

So, for this prophetic reason Jesus had to be raised on the third rather than the forth day; so that both he and the Scriptures that came before him would be vindicated. So that the true and faithful Israel would experience the promises the first Israel was unable to inherit.

I’m sure there are other angles on this as well, but that was roughly my answer in the moment. What have I missed? And what would you have said?