(Numbers 23:2-3:) "Then Balak did as Balaam had {said} [commanded]" and so forth. "Then Balaam said: Stand beside" and so forth, "and he went to a bare height (shefi)." He had been at ease (shafui) about cursing; for until that moment he had been at ease (shafui), but from that moment on he was driven off.
Balaam Goes Alone and Loses His Ease in Parashat Balak
Midrash Tanchuma Buber, Balak 16:2
ויעש בלק כאשר (אמר) [דבר] בלעם וגו', ויאמר בלעם התתיצב על וגו' וילך שפי (במדבר כג ב ג), שפוי היה לקלל, שעד אותה שעה היה שפוי, ומאותה שעה נטרד.