Besides focusing on the persons who benefited from Newton's habitual tenderness, it will be helpful to look too at what we might call some of the patterns of his tenderness.
For the sake of repentance and knowledge of truth, Newton's pattern of tenderness in doctrinal matters was to shun controversy.
The sovereignty of God in freeing people from error or from unbelief also made prayer central to Newton's pattern of tenderness. In a letter about controversy, he wrote a friend:
Newton cared more about influencing people with truth for their good than winning debates. William Jay recounts how Newton described the place of his Calvinism. He was having tea one day with Newton. Newton said, "'I am more of a Calvinist than anything else; but I use my Calvinism in my writings and my preaching as I use this sugar'—taking a lump, and putting it into his tea-cup, and stirring it, adding, 'I do not give it alone, and whole; but mixed and diluted.'" In other words, his Calvinism permeates all that he writes and teaches and serves to sweeten everything. Few people like to eat sugar cubes, but they like the effect of sugar when it permeates it right proportion.
Pastors simply cannot devote much of their time to blowing the trumpet for rigorous intellectual theology. They should see its usefulness and necessity and encourage its proper place. But they cannot be faulted that they mainly have flocks to love and hearts to change. Defending the truth is a crucial part of that, but it is not the main part. Holding the truth, and permeating all his ministry with the greatness and sweetness of truth for the transformation of our people's lives is the main part of his ministry.
(The third of several excerpts from a lecture for pastors by John Piper; the full text and audio can be found here.)