Christians: What the heck does this mean?

Literally it's fortuanate for a human to eat a lion but unfortunate for a lion to eat a human.

It's because the lion is a noble being that takes effort to in fact eat, therefore making a meal well earned.

However a human is sinful and easy pray making us an unappetizing meal.

The Gospel of Thomas has been determined to have been written around the fourth century and is Gnostic in nature, and thus was most likely written by a Gnostic who tried to sell it of as a writing from one of the Apostles. It is a Pseudepigraphic Apocryphal writing.

Lions represent courage and a strong barrier. If you're strong in your faith and trust in god, you can overcome any barrier or eat the lion. Eating the lion, or overcoming the barrier is an action and actions become your habits and your character.

If you are weak in your faith, the barrier will destroy you and it will become your character, weak and fearful.

that's my interpretation.

The gospel of Thomas was determined to be an uninspired writing and possible a fraud.

The Gospel of Thomas is not part of our Holy Bible.

Catholic Christian †

It means we should only eat lions if we have good intentions.

Why would you ask Christians about writings that are not part of the Christian scriptures?

It is nonsense, which is why that book is not in the book of scripture.

I'm not sure, is that part of the Apocrypha?

That's not in the Holy Bible, how would we know?