The issue of people’s hearts is an important and sensitive issue. The heart is called qalb in Arabic because it changes so quickly and frequently (taqallub – alteration, variation, ups and downs). The Prophet (peace and blessings of Allah be upon him) said: “The heart (qalb) takes its name from its constant changes (taqallub). The likeness of the heart is that of a feather at the root of a tree, being turned over and over by the wind.” (Reported by Ahmad, 4/408; Saheeh al-Jaami’, 2364). According to another report: “The likeness of the heart is that of a feather in an empty plot of land, being blown over and over by the wind.” (Reported by Ibn Abi ‘Aasim in Kitaab al-Sunnah. No. 227. Its isnaad is saheeh, see Zilaal al-Jannah fi Takhreej al-Sunnah by al-Albaani, 1/102).