I've been enjoying the work of Richard Sibbes, one of the most influential figures in the Puritan movement during the seventeenth century.
This piece on continuing duty during weakness, is a section I like.
"It should encourage us to duty that Christ will not quench the smoking flax, but blow on it till it flames. Some are loathe to do good because they feel their hearts rebelling, and duties turn out badly. We should not avoid good actions because of the infirmities attending them.
Christ looks more at the good in them which he means to cherish than the ill in them which he means to abolish.
Let us not be cruel to ourselves when Christ is thus gracious. There is a certain meekness of spirit whereby we yield thanks to God for any ability at all, and rest quiet with the measure of grace received, seeing it is God's good pleasure it should be so, who gives the will and the deed, yet not so as to rest from further endeavors. But when, with faithful endeavour, we come short of what we would be, and short of what others are, then know for our comfort, Christ will not quench the smoking flax, and that sincerity and truth, as we said before, will endeavour of growth, is our perfection.
What God says of Jeroboam's son is comforting, 'He only shall come to the grave, because in him there is found some good thing toward the Lord God of Israel' ( 1 Kings 14:13) though only 'some good thing'.
'Lord I believe' Mark 9:24 with a weak faith, yet with faith; love thee with a faint love, yet with love; endeavour in a feeble manner, yet endeavour. A little fire is fire, though it smokes. Since thou hast taken me into thy covenant to be thine from being an enemy, wilt thou cast me off for these infirmities, which, as they displease thee, so are they the grief of my own heart?"