Question:
some matters are not for God to decide but are for man to decide two Jews were arguing and a voice came down saying that some matters are for man to decide where is this written
Answer:
You probably mean “loy bashamayim he” that Hashem gave the power of halachic decision to the Rabbis living in this world.
Sources:
Gemora Bava Metziah 59b, Kesef Mishnah end of 2 Chap. Tumas Tzaraas.
