Mar 10:15 Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child...

Mar 10:15 Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein.
Alternative: The truth is that whoever doesn't take up God's reign as a little child shall not be taken into it.

This verse is another example of the word play in Greek that we usually miss in English. I try to recapture the feeling in the alternative I offer above.  Two related words are contrasted here. "Receive" from dechomai and "enter into" from eiserchomai create the dynamic where the prefixes, acting like our adverbs, determine their different meanings from the same root. "Take up" and "take in" capture the feeling if not the entire meaning. (This wordplay isn't part of the similar verse in Matthew.)

There is also a smaller play on words with the word for "receive" and "child" since a primary meaning of dechomai is "to take by the hand" as we would take a little child by the hand to lead them. This idea gets us even closer to Christ's meaning here, that we must be willing to follow God's lead as a child accepts the guidance of a parent. This means trusting that God loves us and is guiding us, even if his guidance is hidden.

"Verily" is from amên (amen), which is from the Hebrew, meaning "truly," "of a truth," and "so be it." It has not history in Greek before the NT.

"Whosoever" is from hos (hos) which is the demonstrative pronoun in its various forms. It means "this," "that," "he," "she," "which," "what," "who," "whosoever," "where," "for which reason," and many similar meanings.

"Receive" is from dechomai, (dechomai) which means "welcome," "accept," and "entertain" when applied to people. It means "take," "accept," and "receive" when applied to things.

"Kingdom" is from basileia (basileia), which means "kingdom," "dominion," "hereditary monarchy," "kingly office," (passive) "being ruled by a king," and "reign."

"God" is from theos (theos), which means "God," the Deity."

"Children" is from  paidion (paidon). which means "little child" or "young child,"  (up to seven years) "infant" or "young slave."

"Enter into" is from eiserchomai (eiserchomai), which means both "to go into," "to come in," "to enter," "to enter an office," "to enter a charge," (as in court) and "to come into one's mind."

"Therein" is from autos (autos), which means "the same," and the reflexive pronouns, "myself," "yourself," "himself," "herself," "itself," or the oblique case of the pronouns, "him," "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of ones own accord."