We usually expect people to whom we show affection, or we try to help to reciprocate in kind or at least demonstrate some form of gratitude or appreciation. More than this, we would hardly expect them to cause any problems for us or, even worse, harm us. It is no wonder that Jeremiah was upset when those he prayed for were not only causing trouble for him but also plotting to kill him "Is it fair that they are doing this?" Jeremiah complains bitterly to God.
Jesus, in His wisdom, knew that despite the good He brought into the world, He would not be accepted by everyone. There would be those who would reject Him. He knew these people would cause Him trouble and plot to kill Him. In His case, Jesus did not complain to the Father. He accepted all these as part of His mission as the Son of God who had come to serve and not to be served.
Jesus reminded the disciples that the calling of a Christian is not based on position or status or how much good he or she has done. A disciple must be ready to serve despite the circumstances and, if necessary, be willing to give his or her life to fulfil the mission. Christians are called to serve without expecting anything in return. What type of reward will we receive in this world or the next that we leave in God's hands.
Lord, help me be a faithful servant.