Matthew 20-22

When Jesus toLd the parable of the hired workers the closing accusation of the early workers tells us three very important traits of the one who calls the workers. First of all he is persistent. We're not told why he went to look for workers so frequently, but he was looking all the time. Maybe the work is so big he always needs more workers. Maybe the job is most effective with a large pool of laborers. Maybe he knew that every person has the innate desire to work productively. For whatever reason he continued to seek out workers. 
Second his call is universal. He didn't call just Jews, or Romans, or Arabs. His invitation was to all people. Jesus' practice of speaking in riddles and parables does not hide the message that the owner's passion was for all people to be about his work.  
Finally he is generous to all who receive his call. And his generosity is equal to each disciple. Generosity is the hallmark trait of our God. He gives abundantly of his love, his forgiveness, and his grace. So that each believer is not only welcomed but is uniquely gifted to serve God's purpose in advancing his kingdom.
Stuart