Lankeela, think of other biblical phrases such as 'Hallowed be Thy name', as in The Lord's Prayer. That expresses a wish that God's name should be treated with reverence. Today we would prabably say, 'May Your name be made holy.'
It's exactly the same with 'far be it from me', which means, 'May (whatever this bad thing is) be kept far away from me'. The bad thing might be lust, greed or some other wickedness/error etc, but whatever it is I don't want it anywhere near me!
Count_Emmup has confused me, too! The correct form here is certainly 'from' and not 'for' and it has nothing to do with 'forbid' either. 'Far from' is an absolutely standard form in English when suggesting the distance between things; 'far for' is used only in situations such as 'It is too far for me to walk.'
Finally, 'Far be it from me' means 'I want there to be a considerable distance between me and this bad thing!'