Shut out by Maryland justice from work without the jail, he found and did that which needed to be done within "high walls and huge." He was an extraordinary prisoner and was treated with extraordinary consideration by the Warden.

He proved himself a genuine evangel to the prisoners, visiting them in their cells, cheering them by his bouyant and benevolent words, giving them what he had, a brother's sympathy, which to these ill-fated ones, was more than gold or silver.
He indited for such of them as he deemed deserving, letters and petitions to the Governor praying their pardon; and he had the great satisfaction of seeing many of his efforts in this regard crowned with success.
But more than this his imprisonment afforded him an opportunity for a closer acquaintance with the barbarism of slavery than he could possibly have made had he lived otherwise in Baltimore.

A Southern jail was not only the place of detention of offenders against social justice, but of slaves waiting for the next market-day, of recaptured fugitives waiting for their owners to reclaim them.

Here they were huddled and caged, pitiful and despairing in their misery.

Such scenes sickened the young reformer every day.