Learning Compassion for yourself and all beings in the universe in the Past, Present and Future is the key to full enlightenment

 When you understand this you have discovered the most powerful key regarding enlightenment.

However, it is also true that "The way that can be written about or talked about is not the true path or the true way".

This is a true statement also.

The reason for this is that each person is different and will receive enlightenment in a different way.

It's not a one size fits all kind of thing in actuality.

However, the Mahayana is said to be like becoming enlightened with a whole group of people in a 747 traveling across a big ocean.

And the Vajrayana is like being Struck with Lightning where enlightenment is instantaneous. So, the Vajrayana Path is considered to be the Lightning or Diamond Path.