The question is about a verse from Surat Taha: "So I gripped a handful from the tracks of the Messenger."

Perhaps the questioner is referring to the Samiri's statement: "So I grasped a handful from the اثر (footprints/trace) of the Messenger, and I threw it, and thus did my soul entice me." The Samiri saw Gabriel (peace be upon him) on his horse when they came out of the sea, so he took a handful from the trace of his horse's hoof. His soul enticed him into believing that casting it upon something would bring it to life. So he cast it upon the calf he had fashioned, and it began to low. Then he said to the Children of Israel: "This is your god and the god of Moses."