The Cloud of the Lord

When the cloud raised above the Tabernacle, the Israelites made ready to journey. They followed the cloud by day and by night. At night, it was a pillar of fire. When it settled upon the Tabernacle, the Israelites remained where they were. In 40 years, they journeyed 40 times. Sometimes they would stay in one place for a day, sometimes for a week, and sometimes for years. But they always had to be ready to travel. What was God teaching them and what can we learn from this?