וַיַּ֣עַשׂ בָּלָ֔ק כַּאֲשֶׁ֖ר דִּבֶּ֣ר בִּלְעָ֑ם וַיַּ֨עַל בָּלָ֧ק וּבִלְעָ֛ם פָּ֥ר וָאַ֖יִל בַּמִּזְבֵּֽחַ׃
Balak fit ce qu’avait dit Balaam; puis Balak et Balaam offrirent un taureau et un bélier sur chaque autel.
Or HaChaim
בנה לי בזה שבעה מזבחות, "build me on this site seven altars, etc." Bileam was not prepared to reveal to Balak what he had in mind and why as the mutual trust had been breached. Balak carried out Bileam's request, i.e. he displayed confidence in Bileam at this time. When the Torah adds the words כאשר דבר בלעם, (verse 2) it means that he did so without delay.