The verse is talking about the abheda (non-difference) that exists between yantra, mantra and devata.
There is a very similar verse in the Kularnava Tantra's 6th chapter (86th verse).
yantram mantramayam proktam devata mantrarupini | yantre sa
pujita devi sahasaiva prasidati ||
Yantra is endowed with mantras (or mantric qualities); and devata is
of the ...
Basically, Yantras are the sources of energy and it will be activated if we recite a certain mantra constantly. Once it is activated, it will start transmitting its powers to the surroundings. It makes a impact to a human based on his capacity. It is again proportional to his spiritual capacity where he can intake the power. It is a vast subject to get a ...