Midrash for Sotah 93:8
ומי שקיל כולי האי כסף ובגדים הוא דשקיל אמר ר' יצחק באותה שעה היה אלישע עוסק בשמנה שרצים אמר לו רשע הגיע עת ליטול שכר שמנה שרצים וצרעת נעמן תדבק בך ובזרעך לעולם (מלכים ב ז, ג) וארבעה אנשים היו מצורעים אמר רבי יוחנן זה גחזי ושלשת בניו
But had he received all these things? Silver and garments were what he had received! — R. Isaac said: At that time Elisha was engaged [in the study of the Law concerning] the eight kinds of [unclean] creeping things;<span class="x" onmousemove="('comment',' Name of the Chapter in Mishnah Shabbath, XIV, I, cf. Lev. XI, 29ff. ');"><sup>14</sup></span> so he said to [Gehazi], 'You wicked person, the time has arrived for you to receive the reward for [studying the law of] the eight creeping things.'<span class="x" onmousemove="('comment',' Referring to the eight kinds of presents he had accepted. That will be his reward in this world so that he may be punished in the Hereafter. For a fuller version v. Sanh. (Sonc. ed.) p. 735. ');"><sup>15</sup></span>