Jesus washing the disciples feet is one of the utmost acts of humility, and also something of great spiritual importance. About the first we have heard much, so let me add a little different perspective.
The feet of people represent their walk and after a long walk, especially at the time of Jesus, when the roads were so dusty and people wore sandals, the feet needed refreshing. Washing the feet after a long and tiresome journey could be one of the greatest experiences.
Spiritually speaking, it's the same. In our walk with the Lord, we do need refreshing. Sometimes we go through different battles and even when we come out victorious, like Samson, we still need The Holy Spirit's energizing. Remember how Samson, when defeated the Philistines, he was so hungry, and when the Lord provided the so longed drink of water for him, the Bible says Samson's strength revived:
"Because he was very thirsty, he cried out to the LORD, "You have given your servant this great victory. Must I now die of thirst and fall into the hands of the uncircumcised?" Then God opened up the hollow place in Lehi, and water came out of it. When Samson drank, his strength returned and he revived. So the spring was called En Hakkore, and it is still there in Lehi." (Judges 15:18-19)
The interesting aspect I would like to add to this is the fact that Jesus said we are to wash each other's feet, which I understand, besides in the natural sense, as being ready to help each other, in our Christian daily walk with the Lord. When somebody needs refreshing, help them. That's a sign of maturity (Romans 15:1-3).
