Why was the man in Numbers 15 put to death?

Question

Once, when the Israelites were in the wilderness, they came upon a man gathering wood on the Sabbath day. Those who found him as he was gathering wood brought him before Moses, Aaron, and the whole community. He was placed in custody, for it had not been specified what should be done to him. Then the Lord said to Moses, “The man shall be put to death: the whole community shall pelt him with stones outside the camp.” So the whole community took him outside the camp and stoned him to death—as the Lord had commanded Moses.

(nJPS Numbers 15:32-36)

Clearly the halakhah for gathering wood on Shabboth is that the punishment is death, but the halakhah is also that you cannot be put to death without a warning that includes the punishment.

It appears to me that the warning required by Hilkhoth Sanhedrin 12:2 could not have been administered in this case because the punishment had not yet been revealed. If that was the case, he should have only been liable for kareth. So why was he put to death?

Answer 1

Thank you Fred for sourcing it.

The majority opinion in the Talmud is that a warning "this carries the death penalty" is sufficient, without specifying what method of execution. As Rabbi Aryeh Kaplan's Living Torah puts it:

Since it was not specified what must be done to him, they placed him under guard. The death penalty was specified (Exodus 31:14, 35:2). However, the form of the penalty had not been specified (Sanhedrin 78b; Sifri; Rashi).

Sanhedrin 80b:

תניא ושאר חייבי מיתות שבתורה אין ממיתין אותן אלא בעדה ועדים והתראה ועד שיודיעוהו שהוא חייב מיתת ב"ד רבי יהודה אומר עד שיודיעוהו באיזה מיתה הוא נהרג ת"ק יליף ממקושש ורבי יהודה אומר מקושש הוראת שעה היתה

It was taught [Tosefta Sanhedrin 11:1]:

... [incitement to worship idols can be punished without warning] ... but all other capital crimes in the Torah require a congregation, witnesses, and a warning [for the death penalty to be carried out]; and the warning must include that it carries execution by the courts. Rabbi Yehuda says: they must inform him what form of execution will be used.

The original opinion ["it carries the death penalty"] is derived from the wood-gatherer [of Numbers 15, for whom the form of execution was not yet known]. And Rabbi Yehuda says the wood-gatherer was a one-time exception [i.e. God explicitly ordered him executed despite what would generally be an inadequate warning].

Rambam, Laws of Sanhedrin and the Punishments Entrusted to Them 12:2 follows the majority opinion -- all they have to say is "it carries the death penalty."

וכיצד מתרין בו אומרין לו פרוש או אל תעשה שזו עבירה היא וחייב אתה עליה מיתת בית דין או מלקות.

And how do they warn the transgressor? "Cease!" or "Don't do it!", "as this is a sin and you will be liable to the death penalty or lashes."

Answer 2

I recall hearing that it was an Horaas Shaa, a unique ruling just got that time.

Perhaps, it can be understood that since the specific method of death was not commanded yet it was not a necessary part of the Hasraah. At that time the punishment consisted of the fact that he will get killed in some way.

This is different from an התראת ספק, an unsure warning, because in this case this is the whole law.