Fast - motives for obeying
From Bahai9
Fast out of gratitude for firmness in the eternal Covenant[edit]
"O ye loved ones of God! Out of gratitude for firmness in the eternal Covenant arise to serve the threshold of the omnipotent Lord, observe obligatory prayer and fasting, and spend your time in diffusing the sweet savours of God and in spreading the Divine verses. Tear asunder the veils, remove the obstacles, proffer the life-giving waters, and point out the path of salvation. This is what 'Abdu'l-Bahá admonisheth you every morn and eve."
- ('Abdu'l-Bahá, The Importance of Obligatory Prayer and Fasting, sec. 2, no. 5)
Fast for the sake of (the love of) God[edit]
"Fast ye for the sake of your Lord, the Mighty, the Most High...Well is it with the one who fulfilleth My decrees for the love of My Beauty..."
- (Bahá'u'lláh, The Importance of Obligatory Prayer and Fasting, sec. 1, no. 13)