Whether there is an obligation to do penance on all Fridays has been a topic of heated debate on a couple of threads on CAF. I have maintained that there is still an obligation, but some, quoting Jimmy Akin, have maintained that there is not.
Here is the link to his third article:
jimmyakin.com/2004/07/friday_penance_.html
Links to the first two are in it.
I have read his articles and find that his reasoning is very similar to the reasoning used by those who reject Vatican II, but that’s just my opinion.
I’m not trying to get into a debate here, but I just wanted to put emphasis on the most important part of Jimmy Akin’s argument which I feel like many people ignore when dealing with this question, namely, that Canon Law states
very explicitly that if there is a doubt about what a particular canon law, that particular law does not have binding force. The point of his argument is not just that you
could interpret the US Bishops as having removed a strict obligation to penance on all fridays, but that since it can be interpreted that way (even if you don’t think thats the correct interpretation) the law is in doubt, and so, according to Canon Law it is not binding.
Either way, even if you accept his argument (which at least one of EWTN’s Canon Lawyers agrees with) its still something all Catholics really
should do. Even if Jimmy is right and there is no strictly binding obligation (ie, under pain of sin) to penance on fridays outside of lent, its kind of like Good Friday. Its not
technically wrong to spend your good Friday partying it up with others, saving your one full meal for an expensive outing to a fancy seafood restaurant without spending
any time in prayer or reflection on the crucifixtion, there are no Church laws that strictly prohibit this kind of thing, but it goes so strongly against the spirit of Catholicism that there is a very strong “ought” that goes along with observing Good Friday as a special day of reflection on the passion of our Lord. In just the same way, as Catholics, whether or not it is strictly binding, there is a very strong ought that goes along with observing Fridays as days of penance in remembrance of Christ dying on the cross for us sinners.
In summary, while there is a pretty good argument against a Friday penance being strictly binding on US Catholics via the letter of the law, the spirit of the law obliges us to perform at least some form of penance/recollection on Christ’s boundless love and mercy and the unimaginable gift he has given us through his death. Its the greatest gift anyone will ever receive, the least we can do is commemorate it through prayer and reflection (which technically counts as an act of penance for the Friday obligation). Its really so easy to keep that bare minimum that the spirit of the law demands that we keep it.