Why does Genesis 22:7 say "אַבְרָהָם אָבִיו" rather than just "אַבְרָהָם" or "אָבִיו"? It's redundant.
(My kid's question.)
The text is not just dispassionately telling a story. Each word is pregnant with meaning. That is why the initial command was קַח-נָא אֶת-בִּנְךָ אֶת-יְחִידְךָ אֲשֶׁר-אָהַבְתָּ, אֶת-יִצְחָק, 'Take now thy son, thine only son, whom thou lovest, even Isaac'.
Here, the innocent child is turning to his father, whom he trusts, and asking this question. This also establishes parity in preparation for וַיֵּלְכוּ שְׁנֵיהֶם יַחְדָּו.
Such dramatic emphasis is also present in the unnecessary repetitions of וַיִּשָּׂא אַבְרָהָם אֶת-עֵינָיו וַיַּרְא וְהִנֵּה, among many other examples.
Also, otherwise the Torah Codes would be off. ;)