וְאֶת־בְּרִיתִ֖י אָקִ֣ים אֶת־יִצְחָ֑ק אֲשֶׁר֩ תֵּלֵ֨ד לְךָ֤ שָׂרָה֙ לַמּוֹעֵ֣ד הַזֶּ֔ה בַּשָּׁנָ֖ה הָאַחֶֽרֶת׃
Pour mon alliance, je la confirmerai sur Isaac, que Sara t’enfantera à pareille époque, l’année prochaine."
The Midrash of Philo
Why does he say, But I will set up my covenant with Isaac, whom Sarah shall bring forth about this time in the succeeding year? (Genesis 17:21).
On the Change of Names
[267] He goes on to say—thereby heightening the glory of the child to be—that he will be born “in the other year” (Gen. 17:21). And by other year he does not mean an interval of time which is measured by the revolutions of sun and moon, but something truly mysterious, strange and new, other than the realm of sight and sense, having its place in the realm of the incorporeal and intelligible, and to it belongs the model and archetype of time, eternity or aeon. The word aeon signifies the life of the world of thought, as time is the life of the perceptible.