The standard critical Greek text does not say this.
ἐγένετο δὲ ἐν σαββάτῳ διαπορεύεσθαι αὐτὸν διὰ σπορίμων, καὶ ἔτιλλον οἱ μαθηταὶ αὐτοῦ καὶ ἤσθιον τοὺς στάχυας ψώχοντες ταῖς χερσίν.
The
Textus Receptus reads in the following way.
ἐγένετο δὲ ἐν σαββάτῳ δευτεροπρώτῳ διαπορεύεσθαι αὐτὸν διὰ τῶν σπορίμων καὶ ἔτιλλον οἱ μαθηταὶ αὐτοῦ τοὺς στάχυας καὶ ἤσθιον ψώχοντες ταῖς χερσίν.
This is the text behind the King James Version, which is what you quoted. See what
Thayer’s lexicon says about the word δευτερόπρωτος on
www.blueletterbible.org. The word is questionable in origin and probably doesn’t belong to the text appropriately.
It literally says “on the second-first Sabbath,” which doesn’t make sense to me at all.