Celtic knot

Celtic knots date back to the 3rd to 4th century B.C. Drawn in one continuous line, suggesting a continuous movement of time, they represent infinity and eternal life. They symbolize faith, declare love & unity between people, and even protect against evil spirits.
Celtic knots are often associated with the root system of an oak tree.
Celts and especially the druids considered the oak tree sacred. They were a symbol of destiny, power, strength, wisdom, leadership, and endurance. Similarly, the roots of the oak tree are symbolic of the great source of inner strength or divine resources that each person possesses in their own roots.