Answer:
Take off my skin, I won't cry, but you will.
What can go through glass without breaking it?
What can touch someone once and last them a life time?
What is full of holes, but can still hold a lot of water?
Two horses, swiftest traveling, harnessed in a pair, and grazing ever in places. Distant from them.
I appear in the morning. But am always there. You can never see me. Though I am everywhere. By night I am gone, though I sometimes never was. Nothing can defeat me. But I am easily gone.