In 1799, his master came to Philadelphia, and arrested him as his fugitive slave. Ben had an extraordinary degree of intelligence and tact. When his master brought him before a magistrate, and demanded the usual certificate to authorize him to take his human chattel back to Virginia, Ben neither admitted nor denied that he was a slave. He merely showed the certificate of Dr. Rush, and requested that Isaac T. Hopper might be informed of his situation. Joseph Bird, the justice before whom the case was brought, detested slavery, and was a sincere friend to the colored people. He committed Ben to prison until morning, and despatched a note to Isaac T. Hopper informing him of the circumstance, and requesting him to call upon Dr. Rush. When the doctor was questioned, he said he knew nothing about Ben's early history; he lived with him two years, and was _then_ a free man. When Friend Hopper went to the prison, he found Ben in a state of great anxiety and distress. He admitted that he was the slave of the man who claimed him, and that he saw no way of escape open for him. His friend told him not to be discouraged, and promised to exert himself to the utmost in his behalf. The constable who had arrested him, sympathized with the poor victim of oppression, and promised to do what he could for him. Finding him in such a humane mood, Friend Hopper urged him to bring Ben to the magistrate's office a short time _before_ the hour appointed for the trial. He did so, and found Friend Hopper already there, watching the clock. The moment the hand pointed to nine, he remarked that the hour, of which the claimant had been apprized, had already arrived; no evidence had been brought that the man was a slave; on the contrary, Dr. Rush's certificate was strong presumptive evidence of his being a freeman; he therefore demanded that the prisoner should be discharged. Justice Bird, having no desire to throw obstacles in the way, promptly told Ben he was at liberty, and he lost no time in profiting by the information. Just as he passed out of the door, he saw his master coming, and ran full speed. He had sufficient presence of mind to take a zigzag course, and running through a house occupied by colored people, he succeeded in eluding pursuit.