John Gill Commentary Exodus 31:14

"Ye shall keep the sabbath therefore; for it is holy unto you: every one that profaneth it shall surely be put to death; for whosoever doeth any work therein, that soul shall be cut off from among his people." — Exodus 31:14 (ASV)

Ye shall keep the sabbath therefore
Strictly observe it, according to the rules given concerning it:

for it is holy unto you ;
a day that was set apart of God for holy exercises, peculiarly on your account:

everyone that defileth it ;
by doing any servile work upon it, or not observing it in a religious way;

shall surely be put to death ;
by the hand of the civil magistrate; if the law of the Jewish sabbath is now in force, the sanction continues, and the violation of it ought to be punished by a judge with death:

for whosoever doeth any work therein ;
so much as to kindle a fire, and dress any food, by boiling or roasting, or any other way:

that soul shall be cut off from among his people ;
that is, shall die by the hand of the civil magistrate, it being but another phrase for being put to death; though the Jewish writers, particularly Jarchi, understand the former phrase, "put to death", as to be done by a civil magistrate, when there are witnesses and full proof of the case; but this of "cutting off" by the hand of God, by immediate punishment from heaven, when it was done secretly, and there was no proof to be made of it.