Question:How many years of famine did God threaten David with? II Samuel 24:13 and I Chronicles 21:12 have different number of years.
"So Gad came to David and told him; and he said to him, "Shall seven years of famine come to you in your land? Or shall you flee three months before your enemies, while they pursue you? Or shall there be three days' plague in your land? Now consider and see what answer I should take back to Him who sent me" (II Samuel 24:13).
"So Gad came to David and said to him, "Thus says the LORD: 'Choose for yourself, either three years of famine, or three months to be defeated by your foes with the sword of your enemies overtaking you, or else for three days the sword of the LORD - the plague in the land, with the angel of the LORD destroying throughout all the territory of Israel.' Now consider what answer I should take back to Him who sent me" (I Chronicles 21:12).
In Hebrew single letters are used for numbers and it isn't unusual to find a copyist making a mistake in numbers since many of the Hebrew letters look very similar. The letter for three is gimel (ג) and the letter for seven is zayin (ז), while not extremely close, it isn't impossible to imagine a letter being misread and the mistake not being caught. Additional evidence is that the Septuagint transalation of the Old Testament, which dates over a hundred years before Christ has three in II Samuel 24:13.
Others note that there is an interesting parallelism taking place. God offers David the choice of three punishments: three years of famine, three months of losing battles, or three days of plagues. All those threes appear to be purposeful.
Finally, the statement in II Samuel 24:13 could be expressed in a literary form called a synecdochical expression. In a synecdochical expression, the writer speaks of the whole period of time even though part of it has already passed. For example, in Numbers 14:33, God said, "And your sons shall be shepherds in the wilderness forty years, and bear the brunt of your infidelity, until your carcasses are consumed in the wilderness." But at the time of this statement the wandering has been going on for a number of years. In II Samuel 21:1 we read that Israel suffered three years of famine because of Saul's sins in the past. A year later is when David sinned in counting the warriors of Israel. A year would not be enough time to recover from a three year famine. It is possible that the statement in II Samuel 24:13 was an offer of three more years of famine, or a total of seven years of suffering from famine.
The prior three year famine would explain why David avoided that option. Continuing the famine for another three years would have caused huge losses in Israel.
As with other supposed contradictions, reasonable explanations are ignored. Instead, only the difference is pointed out. But these are two different records of the same events. The purpose of the two accounts and their viewpoints are different. II Samuel was written by prophets who witnessed the events. I Chronicles is a historical account looking back at events to emphasize the spiritual significance of the past. You would expect small variances, not because of inaccuracies but because the events are being looked at in different ways. It is just like what happens in a court case. Two witnesses can describe the same events with slight differences and both be completely honest simply because they were standing in two different spots and each focused on different things.
Seen in this way, it would not be odd that II Samuel mentioned the seven years because it explains why David avoided that choice, while I Chronicles mentions the three years because it shows God giving the punishments as a set of three threes.