Rabbi Judah says: "I have lifted up my hand" (Genesis 14:22) means he made them [his gains] a heave-offering, as you say, "and you shall set apart from it a heave-offering of the LORD" (Numbers 18:26). Rabbi Nehemiah says: he made it an oath, as you say, "and he lifted up his right hand and his left hand to heaven and swore by the One who lives forever" (Daniel 12:7). And the Rabbis say: he made it a song, as you say, "the God of my father, and I will exalt Him" (Exodus 15:2).
Abraham's Raised Hand Read as Offering, as Oath, and as Song
Yalkut Shimoni on Torah 75:2
רַבִּי יְהוּדָה אוֹמֵר, הֲרִימוֹתִי יָדִי, עֲשָׂאָן תְּרוּמָה כְּמָה דְּאַתְּ אָמַר "וַהֲרֵמוֹתֶם מִמֶּנוּ תְּרוּמַת ה'". רַבִּי נְחֶמְיָה אוֹמֵר, עֲשָׂאָן שְׁבוּעָה כְּמָה דְּאַתְּ אָמַר (דניאל יב, ז) "וַיָּרֶם יְמִינוֹ וּשְׂמֹאלוֹ אֶל הַשָּׁמַיִם וַיִּשָּׁבַע בְּחֵי הָעוֹלָם" וְרַבָּנָן אַמְרֵי, עֲשָׂאָן שִׁירָה כְּמָה דְּאַתְּ אָמַר (שמות טו, ב) "אֱלֹהֵי אָבִי וַאֲרֹמֲמֶנְהוּ".