Dhammapada verses 92 and 93

92. Those who do not accumulate and are wise regarding food, whose object is the Void, the Unconditioned Freedom — their track cannot be traced, like that of birds in the air.

93. He whose cankers are destroyed and who is not attached to food, whose object is the Void, the Unconditioned Freedom — his path cannot be traced, like that of birds in the air.

– Dhammapada VII – Arahantavagga: The Arahant or Perfected One 92 and 93