A weak Christian does not have clear insight into the close and spiritual failings which cleave to his performances. He sees his gifts and takes notice of his affections, but he does not see the vanity of his mind, the unsoundness of his ends, his carnal dependence upon his duty, self-love, and vainglory. But in the course of time, a grown Christian takes notice of these things in himself. An experienced Christian will take as much notice of his failings in duty as of his ability in it; and though he discerns an enlargement of gifts and graces in himself at times, yet he still discerns much spiritual pride, popular applause, ostentation of gifts, and too much forwardness in setting out his parts (which a weak Christian seldom perceives).

To have a scrupulous conscience about matters of indifference argues for a weak Christian; for so the apostle calls them “weak in the faith” who bind the conscience when the Scripture leaves it free. One believer thought he might eat anything, and another doubted the lawfulness of eating sundry things. Now those who doubted, the apostle called weak; and the weak conscience is apt to be defiled. Not to know our liberty, and to abuse our liberty, is an argument that we have but little grace. Young converts call more things sins than ever God did; they perplex and entangle themselves merely in indifferent things. It is true, there ought to be a conscientious tenderness in all Christians—tenderness of conscience is our duty. But a tormenting, entangling scrupulosity is our infirmity. And yet, as a weak Christian is better than no Christian, a weak faith is better than a seared conscience. (Christopher Love)  

From The Library Of Charles Spurgeon - James Stuart Bell