A.T. Robertson Commentary Matthew 12:13

"Then saith he to the man, Stretch forth thy hand. And he stretched it forth; and it was restored whole, as the other." — Matthew 12:13 (ASV)

Stretch forth thy hand (εκτεινον σου την χειρα). Probably the arm was not withered, though that is not certain. But he did the impossible. "He stretched it forth," straight, I hope, towards the Pharisees who were watching Jesus .