Here is the situation:
“Permit the little children to approach me and don’t forbid them – because the sanctuary of God is present with those such as these. Truly I tell you, whoever does not receive the sanctuary of God like a child will not enter into it.” (Mark 10:14-15)
Then some brought to him some young children, asking that he touch them – and his disciples admonished those who brought them. But when Jesus saw this, he was very displeased, and said to them, (Mark 10:13-14)
Why was Jesus displeased with his disciples?
We can see his answer above. Jesus came to deliver any of us who will accept his teachings - including children. He came to teach us love and loving service to the Supreme Being. This has the effect of saving people - delivering us back to the "sanctuary of God."
How could the sanctuary of God be within the children?
Jesus is speaking of humility and innocent curiosity. Small children are typically endowed with natural humility, innocence, and curiosity. This is because they are new to the world and have not yet been able to learn to navigate it. So they are naturally humble.
This is because the soul is innately humble and innocent. It is only when the soul begins to identify with the body that it becomes entrenched in the consciousness of ownership.
Furthermore, when these natural traits of the soul are fed by an introduction to the Supreme Being - shown with loving devotion to the Supreme Being - this can easily reawaken the soul's natural love for God. This is what Jesus was doing. He was introducing people to God and teaching them how to devote themselves to the Supreme Being.
This is why Jesus stated his disciples needed to become "like a child" in the second sentence. To be "like a child" means to be humble and innocent. It means to trust in Jesus' teachings - just as a young child might trust their parents early in life.
What is the 'sanctuary of God'?
Many translations utilize the term, "kingdom of God" - as if Jesus is speaking of a location.
However, if it is a location - how can a person "receive" a location?
And how can a location be "within" a person?
The phrase "sanctuary of God" is being translated from the Greek phrase, βασιλείαν τοῦ θεοῦ. Here is the breakdown of this phrase, beginning with the last words to the first:
θεοῦ is the Holy Name of the Supreme Being. It is most typically translated to "God" - but its meaning relates more closely to "Supreme Being" or among the early Greeks, "God of the gods."
τοῦ means "of" "in" "by" "with" or "from"
βασιλείαν means, according to Thayer's lexicon, "royal power, kingship, dominion, rule - not to be confused with an actual kingdom but rather the right or authority to rule over a kingdom."
Because the word "kingdom" typically refers to a physical place or territory - sanctuary is a better translation. The reality is that Jesus is not speaking of a location: He is speaking of one accepting the authority of God within one's life.
What is this? It means taking shelter in the Supreme Being. It means putting our life in His hands and considering oneself the subject - the loving servant - of the Supreme Being.
Can we take refuge in God?
Such a position - of taking shelter in the Supreme Being - also assumes that the Supreme Being will protect us. That He is our Best Friend. That He will be there for us and He will deliver us.
The reason Jesus used this terminology back then - βασιλείαν τοῦ θεοῦ - relates back to how citizens would take shelter or refuge in a particular king. During these ancient times, cities and territories were always under attack by other tribes who wanted to conquer them. When citizens accepted a king of their people, they also accepted the protection of the king: They took shelter of that king.
This is the kind of consciousness Jesus is asking his students to attain. If they approach God with humility - like little children - they can "receive" the shelter of the Supreme Being. In this context, to "receive" is to accept.
This means that not only can a person accept or receive the shelter of God: This means that accepting or receiving God's shelter will allow us to enter into His shelter - meaning we will receive His protection and thereby take shelter in Him.
This goes for any of us. If we prayerfully approach the Supreme Being with humility, He will accept us and we can receive His shelter. This requires us to leave behind our pride; our feeling that we deserve something; our feeling that we know something; and our feeling that we are somehow entitled.
It also means leaving behind false humility. If we leave behind these elements, and approach the Supreme Being from within, and we humbly ask Him to guide us and take care of us - He will be there for us. He will give us His shelter.
Can we change our consciousness immediately?
While many imagine this sort of complete surrender as an immediate thing - just having a complete change of heart and surrendering one's life to God - in reality, it is typically a gradual thing: A process.
This is because most of us are filled with so much self-centeredness: So much greed and envy and desires. This consciousness often doesn't change overnight. But if we rely upon the Supreme Being, then He will guide us and teach us - from within and from without - and we will gradually become more and more cleansed of our self-centeredness - as we come to know Him and learn to serve Him.
To accelerate this process of purification and taking shelter in God we can practice the ancient art of praising God's Holy Names. The incantation of God's Holy Names has the ability to purify our heart and mind of our self-centered consciousness - assuming we practice this with devotion - and humility.