What is the ruling on selling ready-made clothes to one who has not reached puberty and wears them below the ankles, and is the seller thereby considered an assistant to him in sin, and is the money resulting from the sale unlawful?

The immature boy is not held accountable and does not sin by letting his garment drag, for the Prophet, peace and blessings be upon him, said: "The pen has been lifted from three... the boy until he reaches puberty." However, the blame falls upon his guardian for allowing him to wear a garment that drags. Guardians of young children must accustom them to the Sunnahs and to abandon transgressions. Scholars have differed on whether the prohibition of letting the garment drag is restricted to arrogance or is absolute; the majority opinion is that it is restricted to arrogance. There is no sin on the seller for selling ready-made clothes unless their predominant use is unlawful. The buyer must use them in a permissible manner and shorten them if they are long. The sin of unlawful use falls upon the user of the garment, not on the seller.