It happened, from the day that the ark abode in Kiriath Jearim, that the time was long; for it was twenty years: and all the house of Israel lamented after Yahweh.
This verse has the nature of a parenthesis, the purpose of which is to reveal how long the ark stayed at its new location.  Therefore, Caird's allegation that, "This verse gives the impression that 20 years have elapsed between the return of the ark to Beth-shemesh and the battle about to be described,"[1] is not accurate.  Such an impression is made only upon persons who fail to see the parenthetic nature of the verse.  This type of writing is often found in Scripture.