TREAD : Strong’s Hebrew to tread, i.e., to trample, crush with the feet: to advance by setting foot upon, tread upon: To tramp or tread heavily so as to bruise, crush, or injure something: to crush under the feet; to encounter successfully the greatest perils from the machinations and persecutions with which Satan would try to thwart the children of God, to tread underfoot, trample on, i.e. treat with insult and contempt.

CRUSH : Strong’s Greek 4937 : to shatter, break in pieces, tread down, to put Satan under foot and (as a conqueror) trample on him, Romans 16:20; also the word “crushed” is used in Isaiah 53:5 But He was PIERCED for our transgressions, He was CRUSHED (Strong’s Hebrew 1792) for our iniquities; the punishment that brought us peace was upon Him, and by His stripes we are healed.

SERPENTS : Strong’s Greek 3789; a snake; evil spirits, demons, Satan. With the ancients the serpent was an emblem of cunning and wisdom; The serpent who deceived Eve and regarded later by the Hebrews as the devil.

SCORPIONS : Strong’s 4651: name of an arachnid, somewhat resembling a lobster, which in warm regions lurks especially in stone walls; it has a poisonous STING in its tail ; symbolic of evil spirits: from the base of skopos and meaning “to PIERCE”; a “scorpion” (from its sting)
Barnes’ Notes on the Bible:

TO TREAD ON SERPENTS : Preservation from danger. “If you tread on a poisonous reptile that would otherwise injure you, I will keep you from danger. If you go among bitter and malignant enemies that would seek your life, I will preserve you.” See Mark 16:18.

SCORPIONS : The scorpion is an arachnid with pincers similar to those of a lobster and a poisonous sting at the end of its jointed tail, Its sting is extremely poisonous, and it is sometimes fatal to life. It is in Scripture the emblem of malicious and crafty men. Luke 11:12; Ezekiel 2:6.

THE ENEMY : Satan. The meaning of this verse is, that Jesus would preserve them from the power of Satan and all his emissaries — from all wicked and crafty men; and this shows that He had Divine Power. He that can control Satan and his hosts that can be present to guard from all their machinations, see all their plans, and destroy all their designs, He is clothed with Almighty Power.

“Then the seventy returned with joy, saying, “Lord, even the demons are subject to us in Your name.” And Jesus said to them, “I saw Satan fall like lightning from heaven. Behold, I give you the authority to TREAD upon SERPENTS and SCORPIONS, and over all the power of the enemy, and nothing shall by any means hurt you. Nevertheless do not rejoice in this, that THE SPIRITS ARE SUBJECT TO YOU, but rather rejoice because your names are written in heaven.” Luke 10:17-20.

“You shall TREAD UPON the lion and adder: the young lion and the dragon shall you TRAMPLE under feet. Because he has set his love upon Me, therefore will I deliver him: I will set him on high, because he has known My name. He shall call upon Me, and I will answer him: I will be with him in trouble; I will deliver him, and honour him. With long life will I satisfy him, and show him My salvation.” Psalm 91:13-16

“He will bring justice to the poor of the people; He will save the children of the needy, And will CRUSH the oppressor.” Psalm 72:4

“The LORD is near to the brokenhearted; He saves the crushed in spirit. Many are the afflictions of the righteous, but the LORD delivers him from them all.” Psalm 34:18-19

“But He was PIERCED for our transgressions, He was CRUSHED for our iniquities; the punishment that brought us peace was upon Him, and by His stripes we are healed.” Isaiah 53:5

“And out of His mouth goes a sharp sword, that with it He should smite the nations: and He shall rule them with a rod of iron: and He TREADS the winepress of the fierceness and wrath of Almighty God. And He has on His vesture and on His thigh a name written, KING OF KINGS, AND LORD OF LORDS.” Revelation 19:15-16

“So the great dragon was cast out, that SERPENT OF OLD, called the Devil and Satan, who deceives the whole world; he was cast to the earth, and his angels were cast out with him. Then I heard a loud voice saying in heaven, “Now salvation, and strength, and the kingdom of our God, and the power of His Christ have come, for the accuser of our brethren, who accused them before our God day and night, has been cast down. And they overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives to the death.” Revelation 12:9-11

“The God of peace will soon CRUSH Satan under your feet. The grace of our Lord Jesus Christ be with you.” Romans 16:20

“He laid hold of the dragon, that SERPENT of old, who is the Devil and Satan, and bound him for a thousand years; and he cast him into the bottomless pit, and shut him up, and set a seal on him, so that he should deceive the nations no more till the thousand years were finished. But after these things he must be released for a little while.” Revelation 20:2-3