Abraham lived in the "land of promise" that God had led him to, yet he did not establish himself there. He lived in a tent. Tents are a temporary dwelling place that can be packed and moved quickly. Abraham died knowing that even though God had led him to that place, it was not the main land. He died looking for a city whose builder and maker was God.
The Israelites lived in tents until they reached the promised land because they were not citizens of the desert. It was not their permanent residence. They were just passing through on their way to a better place.
It's a good reminder to us everyday. When life gets stressful, when riches come or go, when times are good or times are hard, when we are on the mountaintop or in the valley we need to relax because this world is temporary. It is not our home! It is not the mainland! One day, we will leave this place and compared to eternity it will be as nothing more than the blink of eye. As eternity moves on, it will become but a distant memory that fades, except for the part of it that was filled with Christ. That is eternal because He is eternal.
So wherever we are, whatever our circumstances we can RELAX! This is not the mainland!