playing with falsehood and maintaining a right to truth

Two great thoughts, from two of my favorite books:

"You cannot play with the animal in you without becoming wholly animal, play with falsehood without forfeiting your right to truth, play with cruelty without losing your sensitivity of mind. He who wants to keep his garden tidy does not reserve a plot for weeds." - Dag Hammarskjold, as written in Covey's Seven Habits

And...

"Perhaps it is true that 'from the crooked timber of humanity no straight thing was ever made'. But do we need to be straight to point upwards? Do we need to be perfect to be good?" - Jonathan Sacks, in To Heal A Fractured World

Ethics is not about the truths we know; it's about the truths we live. We live lives that are (generally) closer to the second statement than the first. Does exploring themes of falsehood and cruelty change our responses and dull our thoughts? Are we justified in thinking the second statement true, or is that our way of vindicating our own behavior?

Good questions, heavy thoughts, no answers. Discuss amongst yourselves.