45 The term generation is being used here in its widest sense to refer to a full life span. When the chronological factors are considered and the genealogies tabulated, there are four hundred years of bondage. This suggests that in this context a generation is equivalent to one hundred years.
46 Heb “they”; the referent (“your descendants”) has been supplied in the translation for clarity.
47 Heb “is not yet complete.” The sin of the Amorites has not yet reached its limit. The justice of God is apparent. He will wait until the Amorites are fully deserving of judgment before he annihilates them and gives the land to Israel.

In other versions

And they shall come back here in the fourth generation, for the iniquity of the Amorites is not yet complete.”

In the fourth generation your descendants will come back here, for the sin of the Amorites has not yet reached its full measure.”

In the fourth generation they will return here, for the iniquity of the Amorites has not yet reached its full measure.”

After four generations your descendants will return here to this land, for the sins of the Amorites do not yet warrant their destruction.”

And the fourth generation shall return here, for the guilt of the Amorites is not yet complete.”

But in the fourth generation they shall come hither again: for the iniquity of the Amorites is not yet full.

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