Urdu poetry is often written not in direct language but by allusions, hints, indications, suggestions, or metaphorically, and one has often to wrack his brain to understand what the poet is really trying to say. There is often a direct, literal, superficial meaning to it, and an inner, indirect, real meaning which the poet is seeking to convey.
The greatest Urdu poet Ghalib had a horror of the commonplace in poetry and was of the view that poetry should not be in the language of the common man. Hence much of his poetry ( as well as that of many other Urdu poets ) is difficult to understand, for not only is it often highly Persianised, but is also often allegorical and metaphorical.
I may give the example of a sher ( couplet ) of the great Urdu poet Majrooh Sultanpuri
Once Majrooh was invited to a mushaira ( poetry session ) in Pakistan. There he read the following sher ( couplet ) :
बुला ही बैठे अहल-इ -हरम तो ऐ मजरूह
हम भी बग़ल में लिए एक सनम का हाथ चले
Bula hi baithe ahal-e-haram to ai Majrooh
Hum bhi baghal mein ek sanam ka haath chale
The word ‘ahal’ means people, ‘e’ means of, and ‘haram’ ordinarily means Kaaba ( the holiest shrine in Islam ). But in this context ‘ahal-e-haram’ means Pakistan ( since Pakistan had declared itself an Islamic state ).
The word ‘sanam’ has a double meaning. It means idol, as well as a beautiful woman.
So Majrooh says that although he has been called to a holy Islamic land, but he has brought his idol with him i.e. he has not forsaken his beautiful country India, where most people worship idols ( which is forbidden in Islam ).