Eikev - Sheini
Don’t Slack Off
As we have stated, the danger of living in comfort and security is the risk of becoming complacent and slacking off. Moshe cautioned the Jews not to become too pleased with themselves when they enjoy material success because that leads to egotism and neglecting God. The people must never attribute their prosperity to their own skills, rather than to Him.
Similarly, they're about to drive out the mighty nations of Canaan. They mustn't forget that it's really God Who's doing it. (This thought continues in the next aliyah.)