"If your hand or your foot causes you to stumble, cut it off and throw it from you; it is better for you to enter life crippled or lame, than to have two hands or two feet and be cast into the eternal fire." Matt 18:8
There are many things that Jesus said that were illustrative rather than literal. Just as we may today say, "I'm so hungry I could eat a horse" to indicate the size of our appetite, figures of speech, metaphors and hyperbole was used 2000 years ago to the same end.
Beloved, the Lord in now way endorses the maiming of our bodies, but simply points out the importance of salvation. Nothing should keep us from accepting the eternal life he offers, particularly when you consider the alternative. Contextually, we should cease actions (symbolized by the hand and foot) that place us into a sinful situations. We should discard them lest they cost us heaven.
Jesus advises us to just do the right thing. More importantly, we are to prioritize pleasing God above all other pursuits.
Loving Like Jesus,