Adam Clarke on 2 John 1:4

That I found of thy children walking in truth - I have already supposed this Christian matron to be mother of a family, probably a widow, for no mention is made of her husband; and that she was also a deaconess in the church, and one in those house the traveling evangelists preached, and there they were entertained. The children mentioned here may either be her own children, or those members of the Church which were under her care, or some of both. The apostle was glad to find, probably by an epistle sent from herself to him, or from the information of some of the itinerant evangelists, that the work of God was prospering in the place where she lived, and also in her own household. He does not say that all were walking in the truth, but εκ των τεκνων, some of her children; there was a growing and spreading work, and there were many adversaries who strove to pervert them who had already believed, and perhaps were successful in drawing several away from their simplicity.