What Pope Paul VI wrote in 1966 elucidates the forms of penitence:
1 - (higher standard of living areas) witness of asceticism and charity
2 - (lower standard of living areas) promotion of social justice, and prayer.
In the first place, Holy Mother Church, although it has always observed in a special way abstinence from meat and fasting, nevertheless wants to indicate in the traditional triad of “prayer—fasting—charity” the fundamental means of complying with the divine precepts of penitence. These means were the same throughout the centuries, but in our time there are special reasons whereby, according to the demands of various localities, it is necessary to inculcate some special form of penitence in preference to others.(60)
- Therefore, where economic well-being is greater, so much more will the witness of asceticism have to be given in order that the sons of the Church may not be involved in the spirit of the “world,”(61) and at the same time the witness of charity will have to be given to the brethren who suffer poverty and hunger beyond any barrier of nation or continent.(62)
- On the other hand, in countries where the standard of living is lower, it will be more pleasing to God the Father and more useful to the members of the Body of Christ if Christians—while they seek in every way to promote better social justice—offer their suffering in prayer to the Lord in close union with the Cross of Christ.
vatican.va/holy_father/paul_vi/apost_constitutions/documents/hf_p-vi_apc_19660217_paenitemini_en.html