Great meditation masters go to meditate in scary places, like on an island in the middle of a big lake or on high mountain cliffs and tie themselves to a rock so that they don’t succumb to illusions. For instance, if someone seems to appear and invites them to come along, they wake up from the illusion by being held back by their meditation belt. Or while meditating in a cave on a rocky mountain slope, there is the illusion that everything around is a grassy field they want to walk on, so they are held back by the belt and thus wake up from the illusion.
What I mean to say here is that ones awareness needs to be stronger, which is how the luminous quality of ones mind is. Signs of meditation are that ones mind is sharp, clear, more intuitive, and intelligent. If one meditates and ones mind is dull and not clear and intelligent, it means ones meditation isn’t working. One becomes sharper, more intelligent, and knows everything in details if ones meditation is going well. One knows everything when ones mind is clear, just like the sun. One sees everything when the sun shines clearly. One doesn’t even see what is nearby in the fog.
You see, the Buddha meditated like that and he knows everything. Buddha is free of all illusions and sees everything clearly, because his mind is clear. Therefore, great meditation masters can see everybody’s mind, because they are clear. A Buddha knows ones previous life – he knows everything. If he wrote down ones entire life, he would have a lot to tell. He is enlightened and has a clear mind.