You can't motivate a group of people or a Team. You have to motivate people individually, and that motivation has to be in an environment in which that person has a goal - something they want to accomplish in their lives.
Do what's right! Do the best you can and treat others the way you want to be treated because they will ask three questions: (1) Can I trust you? (2) Are you committed? (3) Do you care about me as a person?
After landing his invasion forces on the shores of some country, the sixteenth-century Spanish conquistador Hernan Cortes would immediately burn his own boats. He was sending his army a message: "We can't turn back. Either we succeed here or we die here." Excuses were not an option.