In this poem the poet , William Shakespeare, absolutely confident about his skills, claims that his poem will outlive the ornate marble statues and gold plated monuments built by rich and the powerful. As a result the name of his friend who is referred to in his verse would live for much longer time than the monuments that would stand neglected and tarnished with the passage of treacherous time.
the destructive wars would leave no trace of the statues and the havoc created by them would raise all the magnificent monuments to the ground. However neither war nor their devastations would wipe out the memory of the ones praises in the verse of the poet.
At last, the poet wishes that this praise worthy soul to live in his poetry and in the hearts of his admirers till he finally rises from his grave on the day of judgement and is rewarded by God Almighty.
HOPE THIS ALL WILL HELP U ;)