John 13 leaves us with the example Jesus left to his disciples when he washed their feet. Remembering our identity as sons and servants of God, we are freed up to pour out our cup in service. The Lord doesn’t forget all which we do for him, and he promises a reward. 
 

Hebrews 6:10 

For God is not unjust so as to overlook your work and the love that you have shown for his name in serving the saints, as you still do.