For when I have brought them into the land which I swore to their fathers, flowing with milk and honey, and they have eaten and filled themselves, and grown fat; then they will turn to other gods, and serve them, and despise me, and break my covenant.
Deuteronomy 31:18 I will surely hide my face in that day for all the evil which they have done, in that they have turned to other gods.
Deuteronomy 31:19 “Now therefore write this song for yourselves, and teach it to the children of Israel. Put it in their mouths, that this song may be a witness for me against the children of Israel.
Deuteronomy 31:20 For when I have brought them into the land which I swore to their fathers, flowing with milk and honey, and they have eaten and filled themselves, and grown fat; then they will turn to other gods, and serve them, and despise me, and break my covenant.
Deuteronomy 31:21 It will happen, when many evils and troubles have come on them, that this song will testify before them as a witness; for it will not be forgotten out of the mouths of their descendants; for I know their ways and what they are doing today, before I have brought them into the land which I swore.”
Deuteronomy 31:22 So Moses wrote this song the same day, and taught it to the children of Israel.
The verse centers on "brought", "land", "swore", "fathers", "flowing", "milk", "honey", and "eaten". It is saying that the verse draws attention to "brought" and "land", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 19's "Now therefore write this song for yourselves..." into verse 21's "It will happen when many evils and...", so "brought" and "land" belong inside that flow. In Deuteronomy context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "brought" and "land" with trust shaped by these words, not by a vague optimism outside the passage.