Why is "Zeal" Necessary to Do Good?

It is not difficult to do something which is quite good.... But let someone intentionally define a course for himself of a continuous doing of good, and define the order of it according to what is indicated in the word of God––and this not for one month or for a year, but for one's whole life––and place as a rule to remain in this order unwaveringly; and then, when he remains faithful to this, let him boast of his own power. But without this it is better to close one's mouth.  How many cases there have been in the past and in the present of a self-trusting beginning and building of a Christian life!  And they have all ended and continue to end in nothing.  A man builds a little in his now order of life––and the throws it away.  How can it be otherwise?  There is no strength.  It is characteristic only of the eternal power of God to support us unchanging in our disposition in the midst of the unceasing waver of temporal changes.  Therefore one must be filled abundantly with this power; one must ask for an receive it in order––and it will raise us up and draw us out of the great agitation of temporal life.
Saint Theophan the Recluse      Reference: Path To Salvation, p. 32


Without this Zeal, which involves an intense desire to do His will that comes with a relationship with God, no matter how good intentioned we are, we will find it difficult to keep up doing good by using only our own will and effort.  Saint Theophan points out that continual good works come from God Himself.  For this we need Zeal and must learn how to gain it and nurture it.

How many times have you set your goals at the beginning of a new year, or at any time for that matter, and failed to keep them throughout the year? When you do succeed how often do you then boast about your self-efforts and begin to think of yourself as self-righteous?  What happens then?  Typically, we lose whatever zeal we have and struggle.  For me I can think of many good intentions I have had and have, yet find how difficult it is to continually do His will. I often have difficulty in discerning whether my efforts are the result of my will or His Will. How about you?