May I know the meaning of this poem from Line 48 onward?
There are two main themes to the poem in the lines that you mention.
First, there is the idea that the dead people in this country churchyard were potentially just as good as famous people. It's just that these people never got a chance to become important and famous. You can see this, for example, in lines 57-64.
Second, there is the idea that the speaker identifies himself with poor and obscure people. He hopes that people will remember him in this way -- as an honest and good person, even if not famous. This is the theme of the whole end of the poem, say from Line 93 to the end.
"The Elegy Written in a Country Church Yard" was written by Thomas Gray. It is a death poem which is often written in regards to a specific person's death, but in this poem it is written for the average person, a scholar, who has passed away. The person or persons described in the 28th line down is an ordinary man who lived agood life. The person is not greatly admired or noticeable, but rather an average person who has done average things such as labored in the fields.
The poem goes on to discuss the wealthy and more affluent who have been praised and honored in life unlike the people mentioned above. It is a comparison of those people’s ambitions in contrast to the average person. Yet, in death there is no wealthy or importance from one person to another. The grave makes them equal.
In the poem the poet pays repect to the simple scholar who lived a good life but went relatively unnoticed by others. The poet considers the man to have lived a good life though not an exciting one.
The poem brings to mind that "Death is the great equalizer." (Author unknown)