The 'feet swift to mischief' expresses the eagerness and unhesitating energy of an evil person to carry out the wickedness which their hearts devise. Even though evil thoughts arise in the godly, yet the feet of the godly person, at the promptings of Holy Spirit pricking their conscience as it were, refuses to carry out the bad suggestion of the heart (cf. Isa 59:7).
The "swiftness " of the feet of an evil person is an expression of the vigour and diligence in the manner in which this person hurries to carry out their evil plot against another person. The person that possess "sin--feet" that are swift in running to mischief, exemplify an attitude as if they fear losing time or an oppportunity to cause someone else hurt, harm and pain. Every time (unbeknown to them) God blocks their effort to cause problems in others lives, Satan causes them to become extremely impatient which every delay that occurs in carrying out the evil thing they wish to do. The policy and vigilance, the eagerness and industry, of sinners, in their sinful pursuits, may shame us who go about that which is good so awkwardly and so coldly.
The "irony" of their pursuit of evil lies in sharp contrast to the amount of real energy many Christians exemplify toward the preceipts, principles and truth rooted and grounded in Jesus Christ. It would be great if every child of God the same kind of swiftness toward the "holy and sacred things" that God gives to his children freely as they seek to know him up close and on a more personal level.
Another sharp contrast between the feet that run toward mischief and the "feet" of Ephesians 6:15 that are a part of the "whole armor" of God that are "shodded", that is, prepared for the "Gospel of Peace". The "armored" feet are embodies the "Fruit of the Spirit": feet that promote love, peace, joy, longsuffering, meekness, temperance goodness and faith. According to the Barnes Noble Commentary of Ephesians 6:15, "Christians were to have the principles of the gospel of peace-the peaceful and pure gospel-to facilitate them; to aid them in their marches; to make them firm in the day of conflict with their foes". "They were not to be furnished with carnal weapons, but with the peaceful gospel of the Redeemer; and, sustained by this, they were to go on in their "evangelical" march through the world. The principles of the gospel were to do for them what the greaves and iron-spiked sandals did for the soldier-to make them ready for the march, to make them firm in their foot-tread, and to be a part of their defense against their foes". Every child of God ought to have "feet" of readiness to publish the Gospel. Romans 10:15b says: "How beautiful upon the mountains are the feet of him that bringeth good things, that publisheth PEACE; that bringeth good tidings of good, that publisheth salvation; feet that saith unto Zion, Thy God reigneth! Isa 52:7.
Every Christian should consider himself on his journey from a strange land to his own country, and not only stand every moment prepared to proceed, but be every moment in actual progress toward his home. Every person that possess feet that run swift toward mischief beware! God truly hates mischevious and evil feet. In Judges 4:17, 5:26-31 the evil Sisera's feet carried him toward his death though he tought they were carrying him to safety. In 2 Kings 9:33. Jezebel's "feet" caused her to be thrown out of a window in the palace and trodden under a horsemen's chariot.
Job 18:5-18 gives an apt description of the ultimate fate of the person who lives out their life with "wicked feet" that are swift in running towared mischief:
" The lamp of the wicked is snuffed out; the flame of his fire stops burning. The light in his tent becomes dark; the lamp beside him goes out. The vigor of his step is weakened; his own schemes throw him down. His feet thrust him into a net and he wanders into its mesh. A trap seizes him by the heel; a snare holds him fast. A noose is hidden for him on the ground; a trap lies in his path. Terrors startle him on every side and dog his every step. Calamity is hungry for him; disaster is ready for him when he falls. It eats away parts of his skin; death's firstborn devours his limbs. He is torn from the security of his tent and marched off to the king of terrors. Fire resides in his tent; burning sulfur is scattered over his dwelling. His roots dry up below and his branches wither above. The memory of him perishes from the earth; he has no name in the land. He is driven from light into darkness and is banished from the world". God hates wicked feet!