OF THE ZEALOUS AMENDMENT OF OUR WHOLE LIFE
“As your eye observes others, so again are the eyes of others upon you. How sweet and pleasant is it to see zealous and godly brethren temperate and of good discipline; and how sad is it and grievous to see them walking disorderly, not practicing the duties to which they are called. How hurtful a thing it is to neglect the purpose of their calling and turn their inclinations to things which are none of their business.
Be mindful of the duties which you have undertaken and set always before you the remembrance of the Crucified. Truly ought you to be ashamed as you look upon the life of Jesus Christ, because you have not yet endeavoured to conform yourself more unto Him, though you have been a long time in the way of God. A religious man who exercises himself seriously and devoutly in the most holy life and passion of our Lord, shall find there abundantly all things that are profitable and necessary for him; neither is there need that he shall seek anything better beyond Jesus. O, if Jesus crucified would come into our hearts, how quickly and completely should we have learned all that we need to know!
He who is earnest, receives and bears well all things that are laid upon him. He who is careless and lukewarm have trouble upon trouble, and suffers anguish upon every side, because he is without inward consolation, and is forbidden to seek that which is outward. He who is living without discipline is exposed to grievous ruin. He who seeks easier and lighter discipline shall always be in distress, because one thing or another will give him displeasure.
Oh if no other duty lay upon us, but to praise the Lord our God with our whole heart and voice! Oh if you never had need to eat or drink, or sleep, but were always able to praise God, and to give yourself to spiritual exercises alone; then should you be far happier than now, when for so many necessities you must serve the flesh. Oh that these necessities were not but only the spiritual refreshments of the soul, which alas, we taste too seldom.
When a man has come to this, that he seeks comfort from no created thing, then does he perfectly begin to enjoy God, then also will he be well contented with whatsoever shall happen unto him. Then will he neither rejoice for much nor be sorrowful for little, but he commits himself altogether, and with full trust unto God who is all in all to him, to whom nothing perishes nor dies, but all things live to Him and obey His every word without delay.
Remember always your end, and how the time which is lost returns not. Without care and diligence, you shall never get virtue. If you begin to grow cold, it shall begin to go ill with you, but if you give yourself unto zeal, you shall find much peace and shall find your labour the lighter because of the grace of God and the love of virtue. A zealous and diligent man is ready for all things. It is greater labour to resist sins and passions than to toil in bodily labours. He who shuns not small faults falls little by little into greater. At eventide, you shall always be glad if you spend the day profitably. Watch over yourself, stir yourself up, admonish yourself, and howsoever it be with others, neglect not yourself. Amen.”
Thomas a Kempis
The Mark Of God: Understanding Your "I AM Presence" 