The joke needs the form to stay serious. Allah bachaye, God save us, is what people actually say when something frightening comes up in conversation, and it arrives at the end of every second line. Five times, applied to nothing more dangerous than attractive people smiling at somebody.
The first three couplets are a briefing, delivered by a man with experience. Do not go by how innocent they look. Do not fall for it under any circumstances. They rob you while smiling, so watch the footwork. And then the third couplet: the face may be a moon a hundred thousand times over, God save us from black hearts. The whole convention of the radiant beloved gets held up against what the person is actually like, and does not survive.
Then the fourth couplet turns and points at the preacher, and this is where the poem stops being about romance at all. Inside, a desire for houris and paradise. Outside, a great show of enthusiasm for worship. So: God save us, shaikh ji, from men of God like your good self. The prayer that has been aimed at pretty faces gets aimed at the pulpit without one word of its wording being changed.
The poem never once explains that reversal. Everything said about the beautiful, that they are one thing inside and another outside, that they take you while smiling, that their nature is faithlessness, applies exactly to a pious man who is in it for the rewards. The poem simply says the same sentence twice, once about one crowd and once about the other, and never joins the two dots for you.
Nusrat Fateh Ali Khan's recording for Oriental Star is why anybody has heard this. The poet's name went missing somewhere along the way, which is what tends to happen to poems that qawwals carry: the singer's name travels with the record and the writer's falls off the back of it.
How it rhymes
Every second line closes on the same word — سے اللہ بچائے
, se allah bachaye. That repetition is the radif.
The rhyme falling just before it is the qafiya: The -aalon ending before the refrain: mah-jamalon, husn-valon, chalon, kalon, allah-valon, bhole-bhalon.
Hearing the two land together at the close of every sher is most of what makes this form sound the
way it does.