Why should the assets and liabilities of an existing partnership be revalued when a new partner is

Question:

Why should the assets and liabilities of an existing partnership be revalued when a new partner is to be admitted by the investment of cash in the organization?

Partnership
A legal form of business operation between two or more individuals who share management and profits. A Written agreement between two or more individuals who join as partners to form and carry on a for-profit business. Among other things, it states...