In the year 1758, he attended the yearly meeting at Philadelphia, where he addressed his brethren on the propriety of dealing with such members as should hereafter purchase slaves.  On the discussion of this point he spoke a second time, and this to such effect that, he had the satisfaction at this meeting to see minutes made more fully than any before, and a committee appointed for the advancement of the great object, to which he had now been instrumental in turning the attention of many, and to witness a considerable spreading of the cause.  In the same year, also, he joined himself with two others of the society to visit such members of it as possessed slaves in Chester county.  In this journey he describes himself to have met with several who were pleased with his visit, but to have found difficulties with others, towards whom, however, he felt a sympathy and tenderness, on account of their being entangled by the spirit of the world.

In the year 1759, he visited several of the society who held slaves in Philadelphia.  In about three months afterwards, he travelled there again, in company with John Churchman, to see others under similar circumstances.  He then went to different places on the same errand.  In this last journey he went alone.  After this he joined himself to John Churchman again, but he confined his labours to his own province.  Here he had the pleasure of finding that the work prospered.  Soon after this he took Samuel Eastburne as a coadjutor, and pleaded the cause of the poor Africans with many of the society in Bucks county, who held them in bondage there.

In the year 1760, he travelled, in company with his friend Samuel Eastburne, to Rhode Island, to promote the same object.  This island had been long noted for its trade to Africa for slaves.  He found at Newport, the great sea-port town belonging to it, that a number of them had been lately imported.  He felt his mind deeply impressed on this account.  He was almost over-powered in consequence of it, and became ill.  He thought once of prompting a petition to the legislature, to discourage all such importations in future.  He then thought of going and speaking to the House of Assembly, which was then sitting; but he was discouraged from both these proceedings.  He held, however, conference with many of his own society in the meeting-house chamber, where the subject of his visit was discussed on both sides with a calm and peaceable spirit.  Many of those present manifested the concern they felt at their former practices, and others a desire of taking suitable care of their slaves at their decease.  From Newport he proceeded to Nantucket; but observing the members of the society there to have few or no slaves, he exhorted them to persevere in abstaining from the use of them, and returned home.

In the year 1761, he visited several families in Pennsylvania, and, in about three months afterwards, others about Shrewsbury and Squan in New Jersey.  On his return he added a part to the treatise before published on the keeping of care which had been growing upon him for some years.