But now he became an active one, looking out for circumstances for the exercise of his labours.
"My mind," says he, "was deeply engaged in this visit, both in public and private; and at several places observing that members kept slaves, I found myself under a necessity, in a friendly way, to labour with them on that subject, expressing, as the way opened, the inconsistency of that practice with the purity of the Christian religion, and the ill effects of it as manifested amongst us." In the year 1757, he felt his mind so deeply interested on the same subject, that he resolved to travel over Maryland, Virginia, and North Carolina, in order to try to convince persons, principally in his own Society, of the inconsistency of holding slaves.

He joined his brother with him in this arduous service.

Having passed the Susquehanna into Maryland, he began to experience great agitation of mind.

"Soon after I entered this province," says he, "a deep and painful exercise came upon me, which I often had some feeling of since my mind was drawn towards these parts, and with which I had acquainted my brother, before we agreed to join as companions.
"As the people in this and the southern provinces live much on the labour of slaves, many of whom are used hardly, my concern was that I might attend with singleness of heart to the voice of the true Shepherd, and be so supported, as to remain unmoved at the faces of men." It is impossible for me to follow him in detail, through this long and interesting journey, when I consider the bounds I have prescribed to myself in this work.

I shall say therefore, what I purpose to offer generally and in a few words.
It appears that he conversed with persons occasionally, who were not of his own Society, with a view of answering their arguments, and of endeavouring to evince the wickedness and impolicy of slavery.