And they were leading to him childlings, so that he might touch them. But the students censured them.
And having seen this, Jesus was incensed, and answered them, Release the childlings to come to me; do not stop them, for the realm of God belongs to such as these. Amen, I say to you, whoever does not receive the realm of God as a childling shall absolutely not enter into it.
And having embraced them, he was blessing them, having laid hands on them.
And (as he was) going forth on his way, someone having run up and knelt to him said, Good teacher, what should I do that I might inherit perpetual life?
And Jesus said to him, Why call me good? None are good if the one God is not good. You know the laws. Don't murder, don't commit adultery, don't steal, don't testify falsely, don't injure, revere your father and your mother.
But he was saying to him, Teacher, all these I have observed from my youth.
And Jesus, having gazed at him, was devoted to him and said to him, One is missing to you. Depart, exchange as much as you have, and give to those in need, and you will have treasure in heaven. Then come follow me.
But sobered by the word, he went off grieving, for he was one having many estates.
And having gazed around, Jesus says to his students, With what difficulty those having possessions will enter into the realm of God!
And the students were stupefied at his words. But Jesus, again responding, says to them, Children, how difficult is it to enter the realm of God! Those trusting in possessions -- easier to pass a camel through the eye of a needle than the wealthy to enter into the realm of God.
And they were greatly panicked, saying among themselves, Then who can be delivered?
Having gazed at them, Jesus says, With men, 'can't', but not with God; for everything (is) 'can' with God.
The Rock began to say to him, See, we have released all and followed you.
Jesus was saying, Amen, I say to you, there is no one who has released house or brothers or sisters or mother or father or children or lands on account of me and on account of the good news who shall not get a hundred times it now in this moment, houses and brothers and sisters and mothers and children and lands, with persecution, and in the age that is coming, perpetual life. And many first will be last, and the last first.
[Mark 10:13-31, my very rough translation. These two stories are often treated apart, but it seems to me that in Mark they are clearly two parts of the same story. For instance, Peter (the name is clearly being used as a title here, ho Petros, the Rock) at the end uses a version of the same verb ('release, let go') from the children story and a version of the same verb ('follow') from the landed man story. Little children come having nothing; if you have possessions, you have to relax your grasp on them if you are to receive the kingdom as a little child.
The word we usually translate as 'disciples', of course, just means 'students'. I've used 'childling' because the Greek word is actually a diminutive form. It seems to me that all the translations tone down the word for Jesus's response to the disciples rebuking those leading the children to him. Eganaktesan literally means 'greatly grieved' or 'greatly burdened', but often has to do with anger; the word contains an emphatic element -- Jesus is super-upset.
Much has been said of the somewhat difficult "Why call me good?" exchange. In context, however, the point seems clear -- the man asked him a question, and Jesus's point is explicitly that he already knows the answer, because through the law, God, who is good, has already told him. Jesus is not claiming not to be good, which obviously would not make sense in the present discussion, but saying that if anyone is good, God is, and God has already answered the question. The word I've translated non-colloquially as 'injure' is more often translated as 'defraud' or 'despoil'; but it fundamentally means to take what rightfully is someone else's, which is what 'injure' technically means. The word I've translated as 'exchange' is usually translated 'sell', but I'm not sure that the money is precisely the point, rather than giving his possessions to those who need them more. The rich man has, justly, avoided taking what rightfully belongs to others; now he has to devote what rightfully belongs to him to those who need it.
The rich man is very rich -- the text is clear that he doesn't just have money, he has many productive lands, which is as rich as you can get in the ancient world. But what throws the disciples into consternation is that when Jesus comments on it, he doesn't merely say (as one might sometimes assume from translations and homilies) that it is difficult to get into the kingdom of God if you are rich; he says that it is difficult to get into the kingdom of God if you possess things. Chremata, the word usually translated 'riches', are any kind of useful or needful possessions. The word used in the camel saying, on the other hand, is plousios, which is literally 'wealthy man'. That is to say: How hard it is to enter the kingdom if you have possessions; having a lot of possessions, it is like threading a camel through a needle. (Some manuscripts have not kamelos but kamilos, which is a relatively rare word that in later days means the sort of rope or cable you use for a ship; the Aramaic word, gamla, can also mean either a camel or a large rope, and apparently there are other languages, like Armenian and Arabic, that have similar homonyms. Contrary to the suggestion of some, saying you are going to pass a ship's hawser through an eye of the needle doesn't 'soften' the comparison; camel or cable, it's impossible. The point does not change. And, of course, a number of Jesus' disciples are fishermen. Nonetheless, I think an argument can be made that 'camel' actually fits better. Early Christians quite clearly took it to be 'camel'. Camels are big animals, yes, but they are also associated with wealth and are famously obstinate animals; a camel is not just physically unable to fit through the eye of a needle, it will actively resist going, like the wealthy will actively resist releasing their possessions. And hyperbole is not just about exaggeration but absurdity; and it's notable that later rabbis occasionally use a similar expression but with elephants rather than camels. He could also very well be deliberately using a word that means both. Of course, there are people who will, like camels, balk at the idea of Jesus telling a joke by making a pun, however serious and grave the purpose, and however much this is a common practice of memorable teachers everywhere.)
It's very easy to read the story as a rebuke of people who have more than us, but the point of the story is that relying on possessions at all is a problem, and the disciples are clearly not shocked (and the words for their reaction are quite strong here) at commentary on rich men but about the implications for themselves. If you read the story and say, "Yah, rich people, am I right!", you have, unlike the disciples, not heard what Jesus actually said, because the point, and the thing that astonished them (the word, ekplesso, literally means 'struck, hit, slammed, smote', and, having the implication that you are knocked out of your senses, is used to indicate fright, panic, intoxication, or any sort of overwhelming passion) is that it is difficult for you also to enter the kingdom of God, as long as you are putting your trust in possessions.]