Here the word "foot" is a metonym for desiring to do something sinful that you would do with your feet, such as going to a place you should not go to. Alternate translation: "If you want to do something sinful with one of your feet" (See: [[rc://en/ta/man/jit/figs-metonymy]])
Dying and then beginning to live eternally is spoken of as entering into life. Alternate translation: "to enter into eternal life" or "to die and begin to live forever" (See: [[rc://en/ta/man/jit/figs-metaphor]])
"unable to walk easily." Here it refers not being able to walk well because of missing a foot. Alternate translation: "without a foot" or "missing a foot"