16 “And when you fast, do not look gloomy like the hypocrites, for they disfigure their faces that their fasting may be seen by others. Truly, I say to you, they have received their reward. 17 But when you fast, anoint your head and wash your face, 18 that your fasting may not be seen by others but by your Father who is in secret. And your Father who sees in secret will reward you.” (Matthew 6:16–18 ESV)
“When the heart and mind are deeply exercised upon a serious subject, especially one of a solemn or sorrowful kind, there is a disinclination for the partaking of food. Abstinence therefrom is a natural expression of our unworthiness, of our sense of the comparative worthlessness of earthly things, and our desire to fix our attention upon things above. Fasting, whether total or partial, seems to have been connected with seasons of peculiarly solemn devotion in all ages.” — A.W. Pink
“It is pleasing to God, only so far as it is directed to another object: to train us to abstinence, to subdue the lust of the flesh, to excite us to earnestness in prayer, and to testify our repentance when we are affected by the view of the tribunal of God.” — John Calvin
“I have been in that old church in New England where Jonathan Edwards preached his great sermon, “Sinners in the Hands of an Angry God.” He had a little manuscript which he held up so close to his face that they couldn’t see his countenance. He went on and on. The people in the crowded church were tremendously moved. One man sprang to his feet, rushed down the center aisle and cried, “Mr. Edwards, have mercy!” For three days Edwards had not eaten a mouthful of food; for three nights, he had not closed his eyes in sleep. Over and over again he had been saying to God, “Give me New England! Give me New England!” and when he arose from his knees and made his way into the pulpit, they say he looked as if he had been gazing straight into the face of God. They say that before he opened his lips to speak, conviction fell upon his audience.” — J. Wilbur Chapman
“Scripture records how people fasted to seek God in an intense way, most often conjoined with prolonged prayer, and that fasting was, far from being a mark of empty outward practice, supposed to mark true mourning over loss, true repentance over sin, or true humility in seeking God (Ps. 69:9–12; Is. 58:1–14; Jer. 36:1–9; Jl. 1:13–16; Jl. 2:12–16).” – Harrison Perkins
Soli deo Gloria!