[metmom]

Galatians 1:8-9 But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed. As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.

[ealgeone]

There are parts of Roman Catholicism where they believe an apparition claiming to be Mary promises the following for those who "faithfully" say the Rosary:

11. You shall obtain all you ask of me by recitation of the Rosary.

Further they add this false doctrine:

“There is no problem, no matter how difficult it is, whether temporal or above all spiritual, in the personal life of each one of us, of our families … that cannot be solved by the Rosary. There is no problem, I tell you, no matter how difficult it is, that we cannot resolve by the prayer of the Holy Rosary.

”https://www.catholiccompany.com/getfed/15-promises-to-christians-who-pray-the-rosary/

It should be noted the 15 "promises" and Rosary origin were developed in the 12th century.

Neither are New Testament teachings.

It's just one more false teaching of Roman Catholicism.