וְיַד־יְהוָ֗ה הָֽיְתָה֙ אֶל־אֵ֣לִיָּ֔הוּ וַיְשַׁנֵּ֖ס מָתְנָ֑יו וַיָּ֙רָץ֙ לִפְנֵ֣י אַחְאָ֔ב עַד־בֹּאֲכָ֖ה יִזְרְעֶֽאלָה׃
E a mão do SENHOR estava sobre Elias, o qual cingiu os lombos, e veio correndo perante Acabe, até a entrada de Jizreel.
Rashi
ויתחזק ישראל AND ISRAEL STRENGTHENED HIMSELF — he said, “Although he is my son, he is a king, and I will do honour to him” (Midrash Tanchuma, Bo 6). From this we may infer that we must show honour to a person of royal rank (Cf. Menachot 98a). Similarly, Moses showed honour to the king when he said, (Exodus 11:8) “And all these, thy servants, shall come down to me” (which was only a polite way of saying. “Thou, thyself, wilt be forced to come down to me”); so, too, did Elijah: (1 Kings 18:46) “and he girded up his loins [and ran before Ahab] etc.” (Midrash Tanchuma, Bo 7)
Pat Lechem
Girdle your loins, bare your arms -- i.e. tighten your belt...