At Mass, the priest represents Christ and performs the actions of Christ. Hebrew…

At Mass, the priest represents Christ and performs the actions of Christ. 

Hebrews 5:6; 20; 7:17, 21says Jesus is priest and high priest. The vestments that the priests wear at Mass are the visible expressions of our theological beliefs about the kind of robes worn by Christ at the Last Supper and to the Cross. 

At the Last Supper, Jesus took off his outer clothing (chasuble) and wrapped a towel around his waist and started washing the feet of his disciples (John 13:4) and the robe(s) put on Jesus at the time of his trial(s) and scourging are variously described as a scarlet cloak [Matthew 27:28-31]; a purple robe [Mark 15:17, 20]; a bright/shining robe [Luke 23:11]. 

These descriptions also explains the various liturgical colours of the priests liturgical vestments today.

The priest wears layers of various vestments such as the alb, cincture, amice, stole, and the chasuble or cope. The alb (from the Latin albus, meaning white), the garment in which Pilate clothed Christ and cincture (cord used as a belt to gather the alb at the waist) which can be the colour of the day or liturgical season are a reminder of his chastity. 

The stole which the priest wears around his neck with the ends hanging down in front symbolizes the bonds and fetters with which Jesus was bound during his Passion and the stole will generally be the liturgical colour assigned by the church for the liturgical season or for the particular service and fringe is usually applied to the ends of the stole following Numbers 15:38-39.

The chasuble (outer garment) reminds of his call to charity like Christ who went to the cross for all.

The priest’s readiness to carry the parishioners’ burden charitably is expressed in the traditional prayer that a priest prays before putting on the chasuble – O Lord, who has said, “My yoke is sweet and My burden light,” grant that I may so carry it as to merit Thy grace.

The chasuble is seen as the “yoke of Christ” and reminds the priest that he is “another Christ” in the sacrifice of the Mass and to “put on the new man, who according to God is created in justice
and holiness of truth” (Ephesians 4:24). 

Additionally, the chasuble symbolizes the “seamless garment” worn by Christ when he was led to his crucifixion (John 19:23)