I had read in 'The New Path' that Babaji was Lord krishna in Mahabharat, and again now in reading a book about Sri Ramakrishna Paramhansa I read that Ramakrishna had stated that he was Lord Krishna in Mahabharat times. which is true??or both are true?? please answer.
Was Mahavatar Babaji or Ramakrishna Paramhansa an incarnation of Lord Krishna?
I think some questions, such as this one, must remain unanswered until we, ourselves, attain omniscience. Until we have direct realization, we can only go by what the Masters have passed down to us, thus making our knowledge tentative. I wonder if it really matters.
Paramhansa Yogananda claimed that Babaji had previously lived as Lord Krishna and that he (Yogananda) had been his disciple Arjuna.
He was quite firm about this and if you study their lives, I think you can understand why this is plausible.
My feeling is that Ramakrishna Paramhansa, a saint of broad universality, was speaking allegorically that the spirit of Lord Krishna was alive within him and manifesting through him.
It might be interesting to find sources other than the one you reference. Yogananda knew, personally, many of the disciples of Ramakrishna and never, to my knowledge, mentioned anything that would indicate that great saint as having a previous incarnation as Lord Krishna.