Excerpt from A.W. Pink:
"Many there be who are most anxious to please God and make conscience of all known sins, yet find in themselves so much darkness of mind, activity of rebellious corruption, forwardness in their affections, pervrseness in their wills, yea, a constant proneness to all manner of sins; and, on the contrary, they can perceive so little of the fruits of sanctification, so little evidence of spiritual life, so few signs of Divine grace at work within, that they often seriously doubt if they have received any grace at all.
This is a fearfully heavy burden, and greatly casts down the soul. But here is Divine consolation. Christ pronounces "blessed" not those who are fully of righteousness, but those who "hunger and thirst" after it. Those who mourn over their depravity, who grieve over the plague of their hearts, who yearn for conformity to Christ--using the means constantly--are accepted of God in Christ."