Mahanirvana Tantra

They are praised in all works and in the methods of japa mantra repetition. (14)
Those of the Vedic tradition shrauta-jatiya pertaining to Vedic rites are devoid of power, like serpents without poison.
They were successful in the Krita age and others, but in the Kali age, they are like the dead. (15)
Just as dolls on a wall, though endowed with all senses,
Are powerless to perform actions, so are the other heaps of mantras. (16)
An action performed with other mantras is like union with a barren woman.
There is no attainment of fruit therein; it is merely toil. (17)
In the Kali age, the man who desires success through paths other than those spoken of,
Is a fool who digs a well on the banks of the Jahnavi the river Ganges when he is thirsty. (18)

Having abandoned the Dharma that has come from My mouth, he desires another Dharma.

Now, explaining the ineffectiveness of Vedic mantras in the Kali age and their failure to produce results, He states their lack of success and, because Tantric mantras are effective and grant those respective results immediately, He praises them with verses starting with 'In the Kali age'. (14) "Devoid of power," etc. Those Vedic mantras that were successful in the Krita and other ages, producing their intended results, are all to be understood in the Kali age as powerless or devoid of effect, like serpents without poison, or like the dead—incapable of producing their respective results. (15) "Dolls," etc. Just as those dolls—made of cloth, teeth, and so on, placed on a wall—are incapable of performing actions, even though they possess limbs, so should other mantra-heaps different from the Tantras be understood as incapable of producing results in the Kali age. (16) "Union with a barren woman" is an analogy for an action that does not lead to the intended result; in such an action, there is no fruit, only effort. This is certain. (17-18)