Deuteronomy 7:22
And the Lord thy God will put out those nations before thee by little and little: thou mayest not consume them at once, lest the beasts of the field increase upon thee.
Cross-reference
Deuteronomy 28:63 presents the opposite outcome — instead of gradual possession, total destruction and uprooting for disobedience.
Deuteronomy 11:23 restates the promise to drive out nations, emphasizing they are greater and stronger — reinforcing the need for gradual process.
Exodus 23:29 gives the same reason for gradual conquest — to prevent wild beasts multiplying.
Exodus 23:30 uses the exact phrase 'little by little' — identical instruction for gradual driving out.
Joshua 21:44 records the fulfillment of God's promise of gradual conquest — they gained rest and all enemies were subdued.
Judges 3:1 reveals that the nations left unconquered served as a test for Israel, explaining the 'little by little' process.
Exodus 33:2 confirms God's promise to drive out nations, adding the detail of an angel leading the conquest.
Joshua 15:63 records the failure to drive out Jebusites — a later instance showing the gradual conquest was incomplete.