Apparently, there is a glaring contradiction between 2 Samuel xxiv. 18, and 1 Chronicles xxi. 12; for, where-as the former says the alternative punishment offered David was “seven years’ famine”, in the latter we are told it was “three years”. The explanation is seen in the Septuagint Version, which reads “three” in each case.
We can easily see it was a mere error by a copyist, for the Hebrew characters for three and seven are very similar; simply a dot makes the difference. The explanation is borne out by the uniformity; “three days”, “three months”, “three years”.