The Christian religion teaches that these characteristics (i.e. stability, confidence, and certainty) are found in Christ and can be known and experienced by those who follow him. As the world, and life in general, are like a tumultuous sea, made dangerous by the wind, Jesus is like an anchor for the soul.
The anchor is a very early Christian symbol that has been found in the Roman catacombs. It brings together the cross (#2 right) and the various nautical Christian symbols, like the fish (#1 right), a boat, and a dolphin. The reason why the anchor was used so early in the church may be because the imagery originated in the New Testament letter of Hebrews.
When used today, the anchor represents a Christian's hope in Christ.
- See more at: http://www.religionfacts.com/christianity/symbols/anchor.htm#sthash.T7rNZHEw.dpuf