Someone asked me a very good question:” When I see the nature of my mind, how do I know that it really is the nature of my mind?”
When you meditate and abide free of grasping at whatever arises, so that when a thought arises you do not hold on to it but continue your meditation and the thought dissipates, like a snowflake falling on a lake, this is a sign that you have seen the nature of mind.
When you wonder, ” What is a sign that i have seen the nature of mind?” and you ponder it, you are engaging in discursive thoughts, and so you are grasping at yet another delusion. Ignorance has arisen again, so there is no point in giving it much thought. You must simply allow your mind to rest in its unfabricated nature, without thinking about anything. If you really want to inquire into something, then just investigate whether or not you have been able to liberate your thoughts and afflictive emotions. Nothing else needs to be investigated.
As for the ultimate fruition, the sign of having realized emptiness is that unconditioned, non-conceptual natural compassion will arise within your mind. When you have realized the union of mahamudra and dzogchen, or in other words, when you have realized the nature of mind, great love will arise in your mind. Patrul Rinpoche said, ” There is no greater sign of having realized the nature of mind than the arising of unconditioned compassion.”
– The Wisdom Flame Experiential Commentary on The Ganges Mahamudra