Color green speaks of life sustenance. [Genesis 1:30] Every beast of the earth and to every bird of the sky and to every thing that moves on the earth which has life, I have given every green plant for food.
Like David who tended flocks was a good shepherd; so is the ministry of a pastor.
[John 21:15-17] Jesus said to Simon Peter, “Simon, son of John, do you love Me more than these?” He said to Him, “Yes, Lord; You know that I love You.” He said to him, “Tend My lambs.”  He said to him again a second time, “Simon, son of John, do you love Me?” He said to Him, “Yes, Lord; You know that I love You.” He said to him, “Shepherd My sheep.”  He said to him the third time, “Simon, son of John, do you love Me?” Peter was grieved because He said to him the third time, “Do you love Me?” And he said to Him, “Lord, You know all things; You know that I love You.” Jesus said to him, “Tend My sheep.
Each time Jesus asked Peter; Jesus emphasized that these are not Peter's sheep but His. According to the greatens of Peter's love for Jesus the disciple would tend not his own sheep, but the sheep of Jesus. The greater his love for the Chief Good Shepherd (John 10:14 )the greater would be his ministry.
Pastors do not travel as much as apostles, prophets, evangelists and teachers. They stay attending to the needs of God's flock. Pastors should open the door to Bible Teachers who bring something new and fresh in keeping with their ministry's character. Pastors should also be mindful of the expenses for traveling ministers for they do the harder work; and therefore, they should be sustained with finances. Evangelists and missionaries, apostles, prophets and teachers live from funds raised for them in churches by pastors, for such is their obligation.