Once a Man Twice a Child Explanation.

You were born innocent and pure. That innocent and pure state of mind was recorded by your memory. As you start to grow up, you leave your innocence behind. When you reach manhood or womanhood, if you choose to strive for what is right, it takes you back from where you're coming from. And you're coming from innocence. When you have done this you will recover the innocence you had as a child. In this state is where you will understand what it means to be once an adult but twice a child.

Until you recover your innocence, you cannot enter the kingdom of God. To do that, you have to learn to be as innocent