I assume you are referring to Stephen Spender's poem, My parents kept me from children who were rough?
Spender could be using this poem either as a criticism or praise for his parents for protecting him against children in his neighbourhood who were over-rambunctious and would make fun of him or bully him since he suffered from some disability as a child, having had a problematic foot and a speech impediment. The poem, does however, have universal application and relevance.
The poem is divided into three stanzas and does not have a regular rhyme structure, probably used by the poet to emphasise the irregular and harsh treatment he had been a victim of through the treatment meted out to him by other children. The language is simple and straightforward, which makes the content easily understandable. Also, it enables the speaker to address a younger audience in language which is understood and to which such an audience can relate to, thus creating an awareness of the type of harmful abuse they might knowingly, or unknowingly, dispense to their targets or victims.
It is clear that the speaker distances himself from these 'rough' children - the constant use of 'they' and 'their' makes it clear that the speaker does not share a close relationship with or have any attachment to, these children.
The speaker resents these other children for mocking him: 'who threw words like stones' - their words are hurtful. However, it is clear that these children were either not as economically well-cared for or that they were careless since they 'wore torn clothes' and 'their thighs showed through rags'. It is as if the speaker, in defence, adopts a disdainful and sneering attitude towards the children who are hurting him.
They ran in the street and climbed cliffs and stripped by country streams' - things the speaker was obviously not allowed to do by his very protective parents.
The speaker was terribly afraid of these other children and feared their strength 'more than tigers'. Their muscles were 'like iron' which implies that they were strong because of all the physical activity or that they came from a rough neighbourhood and were hardened by their harsh lives. They obviously bullied the speaker, for their hands were 'jerking', a reference to their constant pulling and shoving and reaching out to him. 'Their knees tight on my arms' makes it painfully obvious that they physically abused him.
He was afraid of the constant teasing by the other boys. Painfully aware of their attitudes, their mockery would rub salt into his already wounded ego. Their actions were harsh. Their 'pointing' is a clear indication of their rejection. They 'copied my lisp' further indicating that they made fun of how he spoke.
In the final stanza, the speaker further illustrates his envy for these children. They 'were lithe'', seemingly he could not be, since he was not given the opportunity to partake in rough activities. However the animal imagery makes it clear that he does not admire them since 'they sprang out behind hedges' obviously to scare him as an animal would do to surprise its prey. They were 'like dogs' further emphasising their savage nature and they would 'bark at our world'. This line clearly emphasizes that the speaker sees himself completely apart from these rough children. They come from entirely different worlds - he, civilized and they not.
The last two lines has much pathos. The speaker attempts to appear brave by looking 'the other way, pretending to smile', but obviously, he cannot. He had the desire to forgive them for the manner in which they treated him, but they, of course, never gave him the opportunity to do so and rejected him outright - 'yet they never smiled'. He did not stand a chance with them.