Priests are required to pray Office of Readings, Morning Prayer, one of the Daytime hours, Evening Prayer, and Night Prayer unless their local ordinary has commuted this in some way.
Sacrosanctum Concilium establishes:
Thanks dylan. I knew there was an obligation but didn’t know the details. But the point is it is part of their vows just as we have marriage vows. If we disobey our vows, it is grave matter. Same for the Priests.
I hope the combination of our posts helps the OP understand the gravity (component of their ordination vow) and rationale (needed for a Priest to be the Shepherd Christ has called him to be) of the obligation for Priests to make this prayer daily.
This is another one. Personally I try to abstain from meat every Friday and I try to attend Mass daily - but the thought that if the Church mandated either, and it became a grave matter not to do it seems sad to me.

I mean - I think that it would be a great practice if everyone abstained from meat on Friday, but I don’t think I’d want those who didn’t to be in danger of hell.
I dunno
Catholig
A little known fact is that we are still required to abstain from meat on Fridays. However, we may substitute abstaining with a corporal work of mercy, charity, or prayer (I believe this is to be prayer related to for the souls of others (in purgatory or in this world).
This is a discipline of the Church designed to inspire holiness. Failure to conform is a missed opportunity to submit and obey and recieve specific graces and blessings. I don’t think it is sinful to not practice the discipline. Anybody know?
Any support for this as a church teaching beyond the reasoning set forth here?
From the Catechism:
2067 The Ten Commandments state what is required in the love of God and love of neighbor. The first three concern love of God, and the other seven love of neighbor.
1853 Sins can be distinguished
according to their objects, as can every human act; or according to the virtues they oppose, by excess or defect; or according to the commandments they violate. They can also be
classed according to whether they concern God, neighbor, or oneself; they can be divided into spiritual and carnal sins, or again as sins in thought, word, deed, or omission. The root of sin is in the heart of man, in his free will, according to the teaching of the Lord: “For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander. These are what defile a man.” But in the heart also resides charity, the source of the good and pure works, which sin wounds. (Editorial comment: A sin against the I AM is greater than a sin against one of God’s creations.)
For me this begs a question: I know a sin directly against God (blasphemy, etc) is most serious. But what about a sin against oneself vs. another. It goes to the second commandment: Love each other as you love yourself. It is a chicken and egg things I know. But are we to first get our personal love sorted out or vice versa. Is my question clear?