What you have there is a ‘mantinada’. A knife with a mantinada curved on the handle is a ‘must’ souvenir from Crete. More about ‘mantinadas’ can be found
here.
This would normally be written in four lines:
Έθιμο το χω από παλιά
μαχαίρι να χαρίζω
μόνο σ’ αθρώπους π’ αγαπώ
και που τσι ξεχωρίζω.
Translation:
It’s been my custom of old
to make a gift of a knife
only to people that I love,
to those I single out.