Why follow the Truth?

Why the preachers are never tired of stressing that truth is to be followed and strictly adhered to in whatever be the situation and howsoever odd be the circumstances. They also lay much emphasis on both the truths -Absolute and Relative. They quote Maharaj Yudhishthhir,  the eldest of the five Pandavas from Mahabharat who while travelling to Swarg (Paradise) on foot through Himalayas lost one of the leg thumbs -the reason being that he spoke a lie during Mahabharat war although this is not actually correct as it was only brutally twisted. The whole theory is a sort of concoction as any truth resulting into killing of some one results into hatya dosh and it can’t be acceptable. Left to me I would prefer to speak a thousand lies if they are capable of saving some lives or are helpful to them in some way or the other. A lie that saves is far better a thousand times than a truth that kills.