Any such commission may provide for such compensation as may be necessary or advisable for the payment of any of its employees and officers in the conduct and management of the hospital, together with the expenses of the hospital, with authority to make such repairs or alterations from time to time as may be necessary and to construct or cause to be constructed or erected such additional buildings as may be necessary or advisable, all of which shall be paid for solely from the income of the hospital, which the commission may use for such purposes. The commission may accept gifts or legacies for the benefit of the hospital. But the commission may not bind the city to any obligation for the payment of any expenses in connection with the management, operation or construction of the hospital or for repairs, new buildings, construction or otherwise without first obtaining the consent and approval of the city council and shall incur no obligations that shall bind the city or city council in any way without first obtaining the consent thereto of such city council.