Midrash for Sanhedrin 214:12
[הוספה מחסרונות הש"ס: רבי יהושע בן פרחיה מאי הוא כדקטלינהו ינאי מלכא לרבנן אזל רבי יהושע בן פרחיה ויש"ו לאלכסנדריא של מצרים כי הוה שלמא שלח לי' שמעון בן שטח מני ירושלים עיר הקודש ליכי אלכסנדרי' של מצרים אחותי בעלי שרוי בתוכך ואנכי יושבת שוממה
whither did he go? — R. Johanan said: He went to bring Gehazi back to repentance, but he would not repent. 'Repent thee,' he urged. He replied, 'I have thus learnt from thee: He who sins and causes the multitude to sin is not afforded the means of repentance.' What had he done? — Some say: He hung a loadstone above Jeroboam's sin [i.e., the Golden Calf], and thus suspended it between heaven and earth [by its magnetism]. Others maintain: He engraved the Divine Name in its [sc. the calf's] mouth, whereupon it [continually] proclaimed, 'I [am the Lord thy God],' and 'Thou shalt have no [other] gods before me.'<span class="x" onmousemove="('comment',' Magical powers were ascribed to the Divine Name; v. p. 446, n. 9. ');"><sup>10</sup></span>