ISB ~ Colossians 2 v23

rigor of devotion:Refers to ascetical practices such as fasting and abstaining from certain kinds of foods. These bodily disciplines are not wrong in themselves, so long as the body is subdued but not despised. Without grace, however, asceticism cannot restrain the selfish urges of our fallen nature. This is possible only through the power of the Holy Spirit (Rom 8:13; 1 Cor 9:27; Gal 5:16). In Jewish mystical tradition, asceticism was a necessary form of preparation to receive visions and embark on heavenly journeys. See note on Col 2:18.