四分律行事鈔資持記 2.1127

2.1127

自作三中。自言現前，非遣他故；律云使淨人作不成。言授與者，律云：自手捉食作，持食置地作，皆不成。

In the three regarding performing it oneself: "Personally present" means not dispatching another; the Vinaya states that having a pure attendant perform it is invalid. Stating "handing over" means that the Vinaya states: holding the food in one's own hands to perform it, or holding the food and placing it on the ground to perform it, are both invalid.