The law is according to his ruling/ his opinion should be taken/ what he says, goes
The course of action is determined by his knowledge. He is the authoritative procedural ruling whose knowledge prevails over the knowledge of all.
("Didn't Amara say, "He went as far as Akiva," he said, "He is true - even if he died on earth, listen to him, all the ease in the earth - he went as if he died outside the earth, but not in the earth" - blessings be upon him)
Translation
Expression (Hebrew)
הֲלָכָה כְּמוֹתוֹ
Definition (Hebrew)
הַהֲלָכָה נִקְבַּעַת עַל פִּי דַּעְתּוֹ. הוּא הַפּוֹסֵק הַהִלְכָתִי הַמֻּסְמָךְ שֶׁדַּעְתּוֹ גּוֹבֶרֶת עַל דַּעַת כֻּלָּם.
("אִי אָמַר הֲלָכָה כְּרַבִּי עֲקִיבָא, הֹוֶה אֲמִינָא - אֲפִלּוּ בָּאָרֶץ, קְמִשְׁמַע לָן, כָּל הַמֵּקֵל בָּאָרֶץ- הֲלָכָה כְּמוֹתוֹ בְּחוּצָה לָאָרֶץ, אֲבָל בָּאָרֶץ לֹא"- בְּרָכוֹת לוֹ ע"א)