The best Quotations

Do you know the writers of the following quotations?

Quotation One can never pay in gratitude; one can only pay ''in kind'' somewhere else in life. - writer
Quotation True happiness is the full use of your powers along lines of excellence in a life affording scope. - writer
Quotation Change hurts. It makes people insecure, confused, and angry. People want things to be the same as they've always been, because that makes life easier. But, if you're a leader, you can't let your people hang on to the past. - writer
Quotation Many have had their greatness made for them by their enemies. - writer
Quotation Eyes lie if you ever look into them for the character of the person. - writer
Quotation It takes two to speak the truth, one to speak, and another to hear. - writer