Commentary for Leviticus 24:15

ונשא חטאו [WHOSOEVER EXECRATETH HIS GOD] SHALL BEAR HIS SIN — i. e. shall be punished with excision if there was no legal warning preceding the offence (Sifra, Emor, Chapter 19 6; cf. Rashi on Leviticus 20:27).

כי יקלל אלוקיו, and thereby transgresses the negative commandment אלוקים לא תקלל, (Exodus 22,27)

איש איש כי יקלל אלוקיו, this refers to someone cursing G’d by using one of the names which describe His attributes, כנויים, without uttering the tetragram that is forbidden to be uttered except by the High Priest on the Day of Atonement in the sanctuary. The individual in question who curses the attribute he had referred to after mentioning it will be dealt with by G’d, ונשא עונו., If, however he uttered the name of G’d’s essence, and had been warned not to, and curses that name, he will be executed, (as happened in the incident described in our chapter).