So, Moses receives ten commandments from God and teaches them to the people. God gives other directions and instructions, too, which Moses also passes on.
But the people begin to disregard and then forget what God told them to do. This displeases him, so eventually he sends a series of wake-up calls, first in the form of judges and later through prophets. Sometimes a foreign power is used to get their attention. (There’s nothing like a crisis to send us scurrying back to God.)
This happens gradually, over time, right? Not necessarily.
Several hundred years after Moses, Nehemiah comes along and reinstates the “festival of booths” — which had not been practiced since the days of Joshua, Moses’ immediate successor. (It is unclear if it is disregarded fully or partially or if it happens during Joshua’s watch or after, but either way, Joshua drops the ball for not perpetuating it.)
It didn’t take hundreds of years for the festival to be dismissed, but less than one generation.
In only one generation, a people can turn away from God — or turn towards him.
Which way do you want to turn?