The Buddhists say this. It used to baffle me completely. But over time it has become a common thought within my head. Follow me here—
Waves coming in and waves going out—you need them both to make the sea
My GF sometimes keeps an empty pantry—sometimes a full pantry. She likes them both—you have to have an empty pantry in order to go shopping and fill it. You have to have a full pantry in order to cook and eat food to empty it. Just like the waves, one side needs the other and the other side needs the one
I used to say Clarity seeks chaos and chaos seeks clarity in my life. When I got too chaotic, I wanted clarity. When I got too clear, I wanted chaos
I observe that I love cleaning my kitchen and I equally love making my kitchen dirty! And then happily observe that it has to be dirty in order for me to clean it and it has to be clean for me to make it dirty! You could say you love to have a clean kitchen (and not a dirty one) but there is no clean kitchen without the dirty one—you can't have a clean kitchen without having had a dirty one. And you can't have a dirty kitchen without having had a clean one—if there was no clean there would be no dirty! If there was no dirty, there would be no clean
With enlightenment and emburdenment, it is the same. Enlightenment (to remove a hindrance) and emburdenment (to place a hindrance) need each other like Tom and Jerry. You can't become enlightened if you were not first emburdened and you can't become emburdened if you were not first without burden. If you are light in this life, then you don't need to get any lighter! If you are heavy, then the only place you can get is lighter
So—to go east one mile is to go west one mile (whatever that means!)
The waves going in and the waves going out are part of the same thing—You can't have one without the other. There is no mess without the cleaning, no cleaning without the mess. No lightness without also heaviness. The same, you can't be full without first being hungry—never hungry without first being full!