If you think you are smart then at the same time you arise your ego

Therefore, all the teachings, all the masters of the teaching, the great Vajrayana or Dzogchen [masters] request highly the devotion first and then the intelligence. This makes sense because we see disciples who were very close to the Buddha they could not develop such view, such realization but only pride, jealousy and hatred. They caused a lot of troubles, even tried to kill the Buddha. So when no devotion, no success at all. So whether you are successful in the path or not, definitely depends on the faith and devotion.

I recommend everyone here: first thing is to check and subdue your ego. If you think you are smart then at the same time you arise your ego. That means you have no faith and you reduce your devotion to the Three Jewels, to the Guru, to the teachings, and your own practice. When you learn too much, when you go around too much, when you see too much, you don’t really work with your mind but you creating more hesitation in your mind. “Oh this is better, the other one is not so good”; but there is no balance in the mind. There are more dualistic thoughts than [if you are] keeping yourself in a humble way.

Hungkar Dorje Rinpoche, “DEVOTION IS ESSENTIAL – Not Intellighence or Smartness”