Personal things cannot be done by another.

Explanation

(English-origin maxim.) Acts that are inherently personal — such as taking an oath, giving testimony, or exercising a personal trust — cannot be performed by a substitute and must be done by the person himself.

Where this applies

• A witness is subpoenaed to testify but sends a friend to give testimony on his behalf; the court refuses because giving testimony is a personal act that cannot be performed by a substitute.
• A public official attempts to delegate the act of taking his oath of office to an assistant; the court rules the oath invalid because swearing an oath is inherently personal and must be done by the officeholder himself.
• A trustee tries to have his secretary exercise the discretionary powers of the trust; the court holds that personal fiduciary duties cannot be delegated to another.