We may think that the Bible's standards are too unrealistic. Look at Jesus' solution to the problem - cut off your hand or pluck out your eye. I don't see a single one who has taken this verse at face value. Even though Jesus' teaching is very strict, it contains important insight. Sin does not begin with an act.
Sin begins with a thought, and results in an act.
Some here who have been physically pure may be very corrupt in their minds, and ready for a fall. I do not believe Jesus really expects us to mutilate ourselves. But I do think he wants us to take sin seriously. Sin can affect us for eternity, unless we do something about it. Even if we gouge out our eyes we can still lust in our hearts.