Just to take a random example -- "love fasting" -- well, fasting per se is not necessary or desirable for a toddler. Even teenagers should not fast severely. But a 6 year old or even a preschooler can participate on some level in the family Lenten practices and perhaps choose his own thing to give up. As for love -- familiarity of custom brings a kind of affection, especially if it is associated with love and respect and has a certain level of challenge, not too severe and not too easy. When I first converted I found it nigh impossible to keep up with my chosen penance (usually giving up chocolate). After years of spectacular failures though I sloowwly made progress and have come to love Lent. My children learned faster than I did ;-).
"Chastising the body" (#11) sounds like hair shirts and so on, but it comes from 1 Corinthians 9:27 and is basically athleticism or physical training for a higher purpose. It's exactly like what my teenage son is doing these days to get himself ready for football practice in the spring, only as St Paul says the prize is imperishable. It's a call to the members of the family to stay in training and not slack.
Run so as to win. Every athlete exercises discipline in every way. They do it to win a perishable crown, but we an imperishable one. Thus I do not run aimlessly; I do not fight as if I were shadowboxing. No, I drive my body and train it....
"Instrument", etymologically, means tool or even furniture or dress. If you remember that Father Dubay said that what we take up and use -- hammer, book, swaddling blanket, uniform -- are extensions of our own selves, then maybe that is a good way to think of these -- as possible distinctives, insignia, means to an end.
It might be nice to go through these prayerfully once a month or once a season and try to figure out positive ways of making them work better in one's individual family. If the whole lot seems overwhelming, one could just target a few that seem in special need of attention.
Behold, these are the instruments of the spiritual art....
1. In the first place to love the Lord God with the whole heart, the whole soul, the whole strength...
2. Then, one's neighbor as one's self (cf Mt 22:37-39; Mk 12:30-31; Lk 10:27).
3. Then, not to kill...
4. Not to commit adultery...
5. Not to steal...
6. Not to covet (cf Rom 13:9).
7. Not to bear false witness (cf Mt 19:18; Mk 10:19; Lk 18:20).
8. To honor all men (cf 1 Pt 2:17).
9. And what one would not have done to himself, not to do to another (cf Tob 4:16; Mt 7:12; Lk 6:31).
10. To deny one's self in order to follow Christ (cf Mt 16:24; Lk 9:23).
11. To chastise the body (cf 1 Cor 9:27).
12. Not to seek after pleasures.
13. To love fasting.
14. To relieve the poor.
15. To clothe the naked...
16. To visit the sick (cf Mt 25:36).
17. To bury the dead.
18. To help in trouble.
19. To console the sorrowing.
20. To hold one's self aloof from worldly ways.
21. To prefer nothing to the love of Christ.
22. Not to give way to anger.
23. Not to foster a desire for revenge.
24. Not to entertain deceit in the heart.
25. Not to make a false peace.
26. Not to forsake charity.
27. Not to swear, lest perchance one swear falsely.
28. To speak the truth with heart and tongue.
29. Not to return evil for evil (cf 1 Thes 5:15; 1 Pt 3:9).
30. To do no injury, yea, even patiently to bear the injury done us.
31. To love one's enemies (cf Mt 5:44; Lk 6:27).
32. Not to curse them that curse us, but rather to bless them.
33. To bear persecution for justice sake (cf Mt 5:10).
34. Not to be proud...
35. Not to be given to wine (cf Ti 1:7; 1 Tm 3:3).
36. Not to be a great eater.
37. Not to be drowsy.
38. Not to be slothful (cf Rom 12:11).
39. Not to be a murmurer.
40. Not to be a detractor.
41. To put one's trust in God.
42. To refer what good one sees in himself, not to self, but to God.
43. But as to any evil in himself, let him be convinced that it is his own and charge it to himself.
44. To fear the day of judgment.
45. To be in dread of hell.
46. To desire eternal life with all spiritual longing.
47. To keep death before one's eyes daily.
48. To keep a constant watch over the actions of our life.
49. To hold as certain that God sees us everywhere.
50. To dash at once against Christ the evil thoughts which rise in one's heart.
51. And to disclose them to our spiritual father.
52. To guard one's tongue against bad and wicked speech.
53. Not to love much speaking.
54. Not to speak useless words and such as provoke laughter.
55. Not to love much or boisterous laughter.
56. To listen willingly to holy reading.
57. To apply one's self often to prayer.
58. To confess one's past sins to God daily in prayer with sighs and tears, and to amend them for the future.
59. Not to fulfil the desires of the flesh (cf Gal 5:16).
60. To hate one's own will.
61. To obey the commands of the Abbot in all things, even though he himself (which Heaven forbid) act otherwise, mindful of that precept of the Lord: "What they say, do ye; what they do, do ye not" (Mt 23:3).
62. Not to desire to be called holy before one is; but to be holy first, that one may be truly so called.
63. To fulfil daily the commandments of God by works.
64. To love chastity.
65. To hate no one.
66. Not to be jealous; not to entertain envy.
67. Not to love strife.
68. Not to love pride.
69. To honor the aged.
70. To love the younger.
71. To pray for one's enemies in the love of Christ.
72. To make peace with an adversary before the setting of the sun.
73. And never to despair of God's mercy.