"Sat", means that which exists forever and is in everything and everywhere. Thus, it is the Supreme Soul which remains immortal. Like God who has the power to burn our sins to ashes, even truth, like fire, has such power.
Although there are several bad qualities in us, we must make up our mind
that "I will not speak falsehood. I always stand for truth".
If purifying seeds are dropped into the muddy waters, they will absorb
the impurities and purify the water.
Likewise, the one virtue of telling the truth will rid humans of all bad
qualities. It is the mind that does many bad things than our actions.
Though we invite a guest, in the mind we think 'this fellow has come now
and might not leave without having food'. Speaking truth is like unlocking
the heart and so we should give up bad thoughts.
Thus, a good thought gradually increases the right action and determination
and removes all the vices from us. Baba resisted the evil-minded from
entering Dwarakamayi. He is Omniscient and can read the thoughts
of everyone in any corner of the world. However, being the Merciful
Father, Baba dispels the evil forces from devotees' hearts, before taking
them closer to Him. Siddique Phalke is one such example. If we enthrone
truth in our hearts, Baba showers His love.