Yancey, Jesus, Chapter 7

Here's how to tell if you are a disciple of Jesus: If you are failing miserably to hear and obey his call, if your perfection falls far short of his command, and you have no hope to make yourself righteous but depend on him completely for forgiveness, then you are his disciple. It means you really have been listening to what he says.
Yancey does an excellent job of showing how the rest of the Sermon on the Mount plays out from the Beatitudes. If anything, the rest of the Sermon is even more strict and harder to hear than its opening lines.
Read Tolstoy if you want to see what it's like to be a follower of Jesus. Yancey spells out in a few pages just how difficult (indeed impossible), and yet how necessary, it is to "be perfect, as your heavenly Father is perfect." Tolstoy was this kind of agonized Christian. Eventually he spent himself trying to follow Jesus. In so doing, he left a powerful legacy of faithfulness.
And then there's Dostoyevsky, the perfect contrast and the perfect fulfillment of Tolstoy. Dostoyevsky saw the grace of Jesus in a way that Tolstoy never did. Where Tolstoy strove for perfection as Christ demanded it, Dostoyevsky saw that perrfection in the Christ that dwelled in him. Tolstoy is law, Dostoyevsky is grace. Both are from God, both are necessary, one fulfills the other.
Thus grace is the final word. Jesus gave his Sermon on the Mount so that we could see the perfection of God, realize how far we are from that perfection, and also find that the forgiveness of Jesus is the only way for the gap to be covered.

Where have you seen yourself fall short?
Where have you seen your own redemption?