It is commonly said, that fasting is intended to make us better Christians, to sober us, and to bring us more entirely at Christ's feet in faith and humility. This is true, viewing matters on the whole. On the whole, and at last, this effect will be produced, but it is not at all certain that it will follow at once. On the contrary, such mortifications have at the time very various effects on different persons, and are to be observed, not from their visible benefits, but from faith in the Word of God.
Some men, indeed, are subdued by fasting and brought at once nearer to God; but others find it, however slight, scarcely more than an occasion of temptation. For instance, it is sometimes even made an objection to fasting, as if it were a reason for not practicing it, that it makes a man irritable and ill-tempered. I confess it often may do this. It is undeniably a means of temptation, and I say so, lest persons should be surprised, and despond when they find it so.
Let it not then distress Christians, even if they find themselves exposed to thoughts from which they turn with abhorrence and terror. rather let such a trial bring before their thoughts , with something of vividness and distinctness, the condescension of the Son of God. He was tempted in all points "like as we are, yet without sin." Surely here too Christ's temptation speaks comfort and encouragement to us.
~St. John Newman
We beseech Thee, O Lord, let Thy gracious favor carry us through the fast which we have begun; that as we observe it by bodily discipline, so we may be able to fulfil it with sincerity of mind; through Jesus Christ our Lord. Amen.