This is from Grace Gems, a website that sends daily devotionals to your e-mail box.  I thought I would share this one.
 
The seeds of every wickedness

(J. C. Ryle, “The Gospel of Mark” 1857)

“But Peter insisted emphatically, ‘Even if I
have to die with You, I will never disown You!’
And all the others vowed the same.” Mark 14:31

See how much ignorant self confidence may
sometimes be found in the hearts of Christians.
The apostle Peter could not think it possible that
he could ever deny his Lord. And he did not stand
alone in his confidence. The other disciples were
of the same opinion. “And all the others vowed
the same.”

Yet what did all this confident boasting come to?

Twelve hours did not pass away before all the
disciples forsook our Lord and fled. Their loud
professions were all forgotten. The present
danger swept all their promises of fidelity clean
away. So little do we know how we shall act in
any particular position—until we are placed in it!

Let us learn to pray for humility. “Pride goes before
destruction, and a haughty spirit before a fall.”

There is far more wickedness in all our hearts,
than we know. We never can tell how far we might
fall—if once placed in temptation. There is no degree
of sin into which the greatest saint may not run—if he
is not held up by the grace of God, and if he does not
watch and pray.

The seeds of every wickedness lie hidden in
our hearts! They only need the convenient season
to spring forth into a mischievous vitality. “Let him
that thinks he stands take heed lest he fall.” “He
who trusts his own heart is a fool.” Let our daily
prayer be, “Hold me up—and I shall be safe!”