Imam Abd al-Rahman Ibn al-Jawzi, Dhamm al-hawa, p. 22. Regarding the importance of the notion of muruwa, see Ignaz Goldziher, Muslim Studies (Chicago: Aldine, 1967), Vol. 1, Chapter 1, »Introductory: Muruwwa and Din,« pp. 11-44
Ibid., p. 475. (The verses to which he refers are the following: Surah VII, »The Heights,« Verse 176; and Surah LXXIV, »The Cloaked One,« Verses 50-51.)