Exodus 28:34-35 (NIV)
The gold bells and the pomegranates are to alternate around the hem of the robe. Aaron must wear it when he ministers. The sound of the bells will be heard when he enters the Holy Place before the Lord and when he comes out, so that he will not die.
The instructions God gave to Moses for the construction and operation of the Tabernacle were very specific. The high priest had to wear a robe with bells around the hem. He had to perform every task in a very particular way when he would enter the Holy Place. This was God's dwelling place. If the high priest were to depart in any way from the instructions, he would die in his duties. It has been said that they would tie a rope around the ankle of the High Priest so that if they ever heard the bells stop ringing, they would know he had died and they would use the rope to pull his body out of there. This is a picture of the complete holiness of our God. The bible says that he is of purer eyes than to behold any sin.
Since Jesus is now our great High Priest, we now can approach the throne of grace with boldness if we have been consecrated to him by accepting his free gift of salvation.
Hebrews 4:16 (NKJV)
Let us therefore come boldly to the throne of grace, that we may obtain mercy and find grace to help in time of need.