R' Ahron Lichtenstein - is religion necessary for ethical conduct?

This article based on a talk by R’ Ahron Lichtenstein is worth reading in its entirety, especially part III:

"Before answering this question, I would like to address the above-mentioned claim that religion is necessary in order to arrive at morality. This argument has been advanced frequently in the modern period. It is a reflection of the secularization of modern culture that religion needs to be sold to masses on the basis of its contribution to morality. In eighteenth-century England, the novelist Henry Fielding advanced this claim; in the nineteenth century, Cardinal Newman rejected it precisely because he said it was a debasement of religion: you are basing religion’s legitimacy purely upon its moral significance…

...Thus, returning to our original question, we surely should not dismiss nor denigrate moral idealism simply because it springs (in certain cases) from secular sources. Certainly, we believe deeply that a moral idealist would be at a much higher level were his morality rooted in yirat Shamayim, were it grounded in a perception of his relation to God and of the nature of a man as a respondent and obedient being. But that surely is not to say that we therefore ought to dismiss totally the possibility or the reality of secular morality. First, we should not do this because it is simply untrue—there are genuinely moral people within the secular community. Second, we ought not do this because, after all, the results are not what we should be seeking. Whether we score points here or there is not crucial. In the process of “scoring points,” we increase sinat achim (fraternal hatred), we sharpen divisions, we heighten tensions; and that is, in and of itself, a moral and ethical problem."