Sufficient Practice.

We must constantly remind ourselves of this, obvious though it may be—in theory and in general. Not everyone who says Lord, Lord, enters the Kingdom of heaven. The [Christian] whose practice is really sufficient for the Kingdom of heaven has to practice not only in Church but also in life, and he has in fact to practice patience, an unassuming spirit, love of his neighbor, honesty and all those virtues in which the children of the world often seem to be superior to us.
Orthodoxy and the faith which truly justifies are two different things. Someone with “a clean slate” may have a heart that lacks God and real love. Church-going is not in itself true Christianity. In fact orthodoxy, respectability and fidelity to the Church can present the danger of self-righteousness and pious hypocrisy.

Everyone hides a certain amount of faulty intention somewhere or other behind his good work. We perhaps admit our failure, but only on condition that others do not take our admission literally. If we are good we make it a reason why we don’t need to improve. . . . We make sacrifices, but mostly they are only a fee exempting us from those we really ought to make. When a call to penance is made, we take it as referring to others, not to ourselves. If our conscience is too uneasy we preach amendment to others. In short, in some respects we are all pagan Christians who refuse our Lord faith. The Lord is still walking among his people and cannot but be astonished at how little faith he finds.

Fr. Karl Rahner, Everyday Faith. Taken from Give Us This Day.

Fr. Karl Rahner (1904–1984), a German Jesuit, served as a theological expert at the Second Vatican Council. He is among the most significant theological and spiritual authors of our time, making a profound contribution to Catholic theology in the twentieth century.