"And He said, If you will diligently hearken" (Exodus 15:26). Rabbi Zeira said, and some say it was Rabbi Hanina bar Pappa: Come and see that the measure of the Holy One, blessed be He, is not like the measure of flesh and blood. The way of flesand blood is that an empty vessel holds, while a full vessel does not hold; but the measure of the Holy One, blessed be He, is not so. Rather, a full one holds, and an empty one does not hold, as it is said, "And He said, If you will surely hearken" [literally, if hearkening you will hearken], that is to say: if you hearken, you will continue to hearken, and if not, you will not hearken.
The Full Vessel That Holds More by the Measure of Heaven
Yalkut Shimoni on Torah 257:3
(שמות טו כו) וַיֹּאמֶר אִם שָׁמוֹעַ תִּשְׁמַע. אָמַר רַבִּי זֵירָא וְאִיתֵימָא רַבִּי חֲנִינָא בַּר פָּפָּא, בּוֹא וּרְאֵה שֶׁלֹּא כְּמִדַּת הַקָּדוֹשׁ בָּרוּךְ הוּא מִדַּת בָּשָׂר וָדָם, מִדַּת בָּשָׂר וָדָם כְּלִי רֵיקָן מַחֲזִיק, כְּלִי מָלֵא אֵינוֹ מַחֲזִיק, אֲבָל מִדַּת הַקָּדוֹשׁ בָּרוּךְ הוּא אֵינוֹ כֵּן, אֶלָּא מָלֵא מַחֲזִיק, רֵיקָן אֵינוֹ מַחֲזִיק, שֶׁנֶּאֱמַר וַיֹּאמֶר אִם שָׁמוֹעַ תִּשְׁמַע, אִם שָׁמוֹעַ תִּשְׁמַע וְאִם לַאו לֹא תִשְׁמַע.