These two sacraments are sacraments of vocation. The Sacrament of Marriage is where a man and woman enter into a lifelong sacramental union that reflects the love of the Church and it’s bridegroom, Jesus Christ. The Sacrament of Holy Orders is when a man is ordained into service into the Church.
Marriage
Marriage can be summed up best in Scripture. St. Paul gives us the best explanation of the sacramental nature of marriage toward the end of his great Epistle to the Ephesians. In that letter he tells us that the love of man and woman in marriage is intended to reflect the love between Christ and his Church. Just as Christ loves the Church and gives himself to her, so a man is to love his wife and give himself to her. And just as the Church loves Christ and gives herself to him, so a woman is to love her husband and give herself to him. This means that every marriage is a sign to the world of Christ’s own love for the Church and the Church’s own love for Christ. Christian marriage, then, is a unique witness to the world of the love that exists between Christ and his bride, the Church.
Typically in the Church, a couple that wants to marry will go through a process called Pre-Cana. The Pre-Cana marriage program will provide couples with instruction, and guidance on topics and potential challenges they will face in marriage. The goal of Pre-Cana is to expose couples to potentially difficult or challenging topics or ideas they will face in marriage early, so they know how to navigate them more effectively. The Sacrament of Marriage must occur in a Catholic Church, with a Catholic Priest presiding over the ceremony.
Holy Orders
The Sacrament of Holy Orders is when a man commits himself to the vocation of serving God and is ordained a priest in the Catholic Church. A Priest is ordained to preach the Gospel, celebrate the Sacraments and is entrusted to care for and provide spiritual guidance to his presiding Church and local community.
A priest is ordained at the completion of his training. A person who feels called to the priesthood will join a Catholic Seminary, where they will undergo years of intense theological study. Once they complete all their training and graduate from the Seminary, they will begin the transition into priesthood. This typically involves a small period of time as a parish deacon, serving as almost an understudy to the parish priest. Then, once their training and preparation is complete, they will be ordained by the bishop of their diocese. Upon completion of the Sacrament of Holy Orders, they will be assigned a parish and begin their life as a Catholic Priest.
It is very uncommon for a person to receive both these sacraments of vocation. Traditionally most Catholics are called to one vocation or the other. That doesn’t mean there aren’t exceptions though, but those exceptions are very rare and handled on a case by case basis. If you feel called to the priesthood or feel a desire to learn more about these sacraments, reach out to your local parish priest.