Problem is, today we tend to either "spiritualize" our walk with God to the point that we ignore the practical needs in society, or we make it all about the "good works" we do, and fail to recognize the need for us to rely on the power of God's Spirit. Jesus makes the point through this parable that our walk with Him in this world isn't only about the life we'll have with Him after death, but the life we have with him NOW! He was teaching that eternal life starts here on this earth when we accept Him as our Savior! There is no dichotomy in our spiritual/physical walk. Eternal life is lived in the spiritual realms as well as the very mundane things of this world.
By the way, how do we most effectively share the gospel? By preaching on a street corner with a bull-horn? No, not really. It's by being in relationship with people--genuine, real, messy, relationships. That's where people see Jesus, that's where they see God's love, if it is indeed in us.
It's so easy for us to do what the priest and the Levite did in the story of the Good Samaritan...real ministry is uncomfortable at times, awkward, messy... That's part of the point of the story I believe. We all need to get into the mess--we are not perfect people, yet we are being sanctified as we walk with Jesus and in genuine relationships with others. Because of Jesus, we CAN love God and our neighbor as He asks us to.