On the day the tabernacle, the tent of the covenant law, was set up, the cloud covered it. From evening till morning the cloud above the tabernacle looked like fire. 16 That is how it continued to be; the cloud covered it, and at night it looked like fire. 17 Whenever the cloud lifted from above the tent, the Israelites set out; wherever the cloud settled, the Israelites encamped. 18 At the Lord’s command the Israelites set out, and at his command they encamped. As long as the cloud stayed over the tabernacle, they remained in camp. 19 When the cloud remained over the tabernacle a long time, the Israelites obeyed the Lord’s order and did not set out. 20 Sometimes the cloud was over the tabernacle only a few days; at the Lord’s command they would encamp, and then at his command they would set out. 21 Sometimes the cloud stayed only from evening till morning, and when it lifted in the morning, they set out. Whether by day or by night, whenever the cloud lifted, they set out. 22 Whether the cloud stayed over the tabernacle for two days or a month or a year, the Israelites would remain in camp and not set out; but when it lifted, they would set out. 23 At the Lord’s command they encamped, and at the Lord’s command they set out. They obeyed the Lord’s order, in accordance with his command through Moses.
Numbers 9:15-23 (NIV)