Summary: Our spiritual battle has to do with our memory. If we remember who God is and what he has done then we will overcome. But we tend to forget what we have to remember.
Joshua chapter 12 we just read is divided into two parts. The first part, verses 1 through 6, talks about 2 kings east of Jordan River, King Sihon of the Amorites and King Og of Bashan both of whom had been killed and their land was taken by the Israelites under the leadership of Moses.
Then the second part, verse 7 through verse 25, talks about 31 kings that Joshua and the Israelite armies defeated on the west side of the Jordan
But, Moses had already described in detail how they had fought and won the battles against the King Og of Bashan and the King Sihon of the Amorites east of Jordan River. And Joshua also had explained in detail how they had fought and won in the battles against Canaanites Kings. Thus they had been involved in so many battles and each battle was so significant and each victory demonstrated how mighty and faithful God was.
Obviously, the summary of all those battles could serve the people as a reminder of God’s love and work in a simple form. I believe remembrance is such a big deal in our spiritual life because we tend to forget so easily important matters unless we keep a record or summary in writing. I would even say our spiritual battle has to do with our memory. If we remember who God is and what he has done then we will overcome. But we tend to forget what we have to remember.
Do you remember how long did it take before the Israelites began to complain after they experienced God’s mighty hand in rescuing them through the 10 plagues and crossing the red sea? It took only several days. Within a few days, they forgot why they left Egypt and how they left and began to complain, and later on, they even wanted to go back to Egypt.
This is why God commanded them to keep Sabbath. “You shall remember that you were a slave in the land of Egypt, and the LORD your God brought you out from there with a mighty hand and an outstretched arm. Therefore the LORD your God commanded you to keep the Sabbath day.” (Deut 5:15)
In addition, God commanded His people to commemorate Passover annually to remember God’s mighty work and His faithfulness. "Honor the LORD your God by celebrating Passover in the month of Abib; it was on a night in that month that he rescued you from Egypt.” (Deut 16:1)
The reason why God made them observe the Sabbath and the Passover was because He wanted them to remember His salvation and His grace for all their life so that whenever they were in doubt and in trouble, they could remind of God's salvation and His grace to restore faith and strength, thus thanking and praising God.
However, the Israelites weren't following God's command. The Bible doesn’t have many records of how the Israelites kept the sabbath, but, concerning Passover do you remember how many times they celebrated Passover while they were in the wilderness for 40 years? Only once as they departed from the mountain Sinai, that's all which means they hadn’t celebrated Passover for almost 40 years in the wilderness.
Not only that, later God rebuked the Israelites through Amos the prophet saying “Did you bring to me sacrifices and offerings during the forty years in the wilderness, O house of Israel?” (Amos 5:25) They didn’t offer offerings or sacrifices even once during the 40 years in the wilderness, meaning they didn’t have any appreciation, gratitude toward God who saved them and was leading them to the promised land. Rather, they kept on complaining and blaming the leaders and even God Himself because they forgot what God had done for them.
Unfortunately, this wasn’t just during the period in the wilderness. The 2nd chapter of the book Judges talks about what happened as soon as Joshua and the people in his generation passed away. The new generation did not acknowledge the LORD or didn’t remember the mighty things God had done for Israel. They abandoned the LORD, the God of their ancestors, and They went after other gods.
And since the Passover under the leadership of Joshua, there is no mention of any Judge or King celebrating Passover until Hezekiah. This means for 7 hundred years or so they haven’t celebrated the Passover, except Samuel though there is no clear mention. In fact, the history of the nation Israel is a history of how unfaithful they were while it is a history of how faithful God is in spite of their unfaithfulness.
God is God who is faithful and who wants His people to remember what He has done for them.
So when the whole nation of Israel had finished crossing the Jordan, the LORD instructed Joshua to, “Choose twelve men, one from each tribe, to take up twelve stones from the middle of the Jordan and set them down as a memorial to their children so that they might remember the waters of Jordan were cut off when Israel passed through into the land.