Considered, besides, in its effects on us, how sad is venial sin! See
what it did in the Apostles. For three years they had lived with Our
Lord, seeing Him, listening to Him, rejoicing in His miracles and in His
particular and private explanations. Did they profit by them? Not at
all. They did not even go so far as to correct themselves of their
defects. Their ambition, their jealousy, their self-love still
domineered them. What, then, was the obstacle? Venial sin, for the
Gospel records their faults, and they were but venial faults, only
venial faults. But see, whither they conducted. Behold them fleeing from
the Garden of Olives, and Peter denying his Master. Judas, also, had
lived with Our Lord, and his infidelity began with only small faults of
cupidity.
--St. Peter Julian Eymard
Taken from The Catholic Breadbox.