Why Does Jesus Say His Disciples 'Will Take Up Serpents' (Mark 16:18)?
This verse is a promise of protection—not a command—to those individuals God has called to preach the gospel (notice verse 15).
An example of this occurred on the Mediterranean island of Malta, where the apostle Paul was bitten by a poisonous snake while gathering firewood (Acts 28:1-6). It is important to realize that he was not purposely handling the snake. Rather, this incident was an unexpected accident, and God miraculously protected His servant as He had promised!
Deliberately handling poisonous snakes or drinking deadly liquids expecting God's protection is definitely contrary to Christ's teachings. In Matthew 4:5-6, Satan tries to persuade Christ to throw Himself down from a pinnacle merely because He had a promise of protection. However, Christ rebukes Satan because he is misapplying the scripture he quotes from Psalm 91:11-12. Jesus says to Satan, as He says to anyone who delights in misapplying God's promise of protection, "You shall not tempt the LORD your God" (Matthew 4:7; quoted from Deuteronomy 6:16). Therefore, the practice of deliberately handling deadly snakes or drinking poisonous liquids is definitely wrong!