Amulets & Talismans for Protection
For many years, Amulets were intended to guard their owners' families and property from disasters, spells, bad luck or bad fortune and evil spirits. Some were used to heal sickness and cure infertility; others were meant to shield the traveler from peril, to promote success and bliss, and even to secure the positive and balanced relationships.
Why should people carry God's names on them?
"So they will put my name on the Israelites, and I will bless them." (Numbers 6:27)
The literal meaning of this verse is that carrying God's name on someone's body brings God's bliss to his life.
The general idea behind carrying amulets with God's holy names on a person's body is that by doing so that person marks himself as part of God's territory, outside the domain of any dark forces.
This idea gives another meaning to: “You shall not carry the name of the LORD your God in vain, for the LORD will not hold anyone guiltless who misuses his name." (Exodus 20:7). In this case the word - "carry", means literally carrying God's name on a person's body. In this case, carrying God names in vain could mean behaving in an inappropriate behavior while carrying God's name.
An example for this ancient custom can be found in the Biblical law that King David and every king in Jerusalem had a whole scroll of the Five Books of Moses carried with him wherever they went as an amulet for protection. However, the king had to be careful not to take the Torah Scroll through unclean places like the bathroom etc. (Talmud, Sanhedrin, page 21b), hence, misusing the name of God by carrying it to the wrong places. We can learn from this that when we carry Amulets & Talismans as jewels or any similar artifacts, we should cover them under our cloths or in a bag as we enter unclean places.