Meaning
To face such hardship that one recalls one's earliest days in misery.
Literally: to remember the milk of the sixth day
See it in the verse
Chhatthi ka doodh yaad aana in Iqbal’s couplets
Aata hai yaad mujh ko guzra hua zamana
Wo bagh ki baharen, wo sab ka chahchahana
Wo bagh ki baharen, wo sab ka chahchahana
I remember the time that has passed — those springtimes of the garden, that chorus of every bird singing.
Freedom · Restlessness
Ai aab-e-rud-e-Ganga wo din hai yaad tujh ko
Utra tere kinare jab karwan hamara
Utra tere kinare jab karwan hamara
O waters of the river Ganga, do you remember those days — when our caravan first halted upon your banks?
Unity · Love
Kabhi chhodi hui manzil bhi yaad aati hai rahi ko
Khatak si hai jo sine mein gham-e-manzil na ban jae
Khatak si hai jo sine mein gham-e-manzil na ban jae
Sometimes the traveller remembers even the destination he left behind; I fear this faint ache in my chest may grow into grief for a settled place.
Restlessness · Aspiration