What exactly did Yeshua mean when he said in Luke 10:19, “Remember, I have give you authority; so you can tread on snakes and scorpions.”
Is this some type of Jewish idiom?
No, this is not a Jewish idiom. It is a reference to the Messianic Age (The Millennium when Yahshua Rules for 1000 years). In Isaiah we read:
Isa 11:8 And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice’ (viper) den.
Isa 11:9 They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of YHVH, as the waters cover the sea.
Some churches use this as well as Paul’s statement to handle dangerous snakes and drink poisons without harm coming to them in their church services. Unfortunately, many die. They fail to realize what Yahshua said to hasatan when he challenged Him to jump from the pinnacle of the Temple: “You shall not provoke the L-r your G-d.”