The history of all approved apparitions shows that the
  Church requires unequivocal evidence of supernaturality.
  This can be cures, as at Lourdes and Beauraing, or a
  supernatural prodigy, as at F tima. The reason from the
  Church's mystical theology is that most mysticism (as
  both St. Thomas Aquinas and St. John of the Cross teach)
  is mediated by the angels (who have a created angelic nature).
  What the good angels can do the bad angels can imitate, so
  that many so-called "supernatural" phenomena are merely
  preternatural (above human nature, but not above the angelic
  nature). At Garabandal this would include the ecstasies, the
  ecstatic walks, the returning of rosaries and medals to the
  proper owners and so on. None of these things, much less
the miraculous photos, rosaries turning gold etc. of more
  recent alleged apparitions, proves anything to the Church
 about the divine origin of a phenomena. In the absence of
 some clear supernatural proof neither the local bishop or
 Rome is likely to approve an apparition.
 While two commissions convened by bishops of Santander,
 Spain, have stated that there were no phenomena which
 would authentic the events as certainly supernatural they
 did not condemn the message. In this regard, the first
 commission stated, "we have not found anything deserving
 of ecclesiastical censure or condemnation either in the doctrine
  or in the spiritual recommendations that have been published
  as having been addressed to the faithful." The bishop who
 called the second commission, Bishop del Val, upon retiring
from office stated in an interview that the message of Garabandal
 was "important" and "theologically correct." Indeed, some of
the prophetic elements of the message can be found in private
 revelations which have been approved since the initial decision
 on Garabandal in the 1960s. For example, the concept of a
worldwide warning can be found in the Diary of Blessed, soon
 to be Saint, Faustina (Diary n.83), and both the message of
Divine Mercy given to her (Diary n.1588) and that of Akita
(approved by the local bishop) speak of chastisement if mankind
 does not ultimately repent. In October 1997 Archbishop Capovilla
 speaking of the Third Secret of F tima, which as Pope John XXIII's
 secretary he was privileged to read at the time it was opened,
stated that it spoke of a "divine intervention" and a "supernatural
 manifestation." Similar prophetic content can be found in the
writings of Elizabeth Canori-Mora and Mary of Jesus Crucified,
 both of whom were beatified by Pope John Paul II, as well as
  in prophecies given by God to Blessed Anna Maria Taigi and
  St. Caspar del Bufalo. Finally, the principal promoter of Garabandal,
  Joey Lomangino, testifies that it was Blessed Padre Pio who told
  him the Blessed Virgin was appearing at Garabandal and he
  should go.
 It seems, therefore, that notwithstanding the decisions of two
 commissions accepted by the bishops of Santander, that there are
  reasonable grounds for individual Catholics to find Garabandal
  credible. The children themselves predicted that the message of
  Garabandal would be approved with difficulty, but in sufficient
  time to spread it. Perhaps this means that the "warning" (a
  clearly supernatural event) must occur first for approval to be
given. Given the seriousness of the times we do well to heed
 the message of conversion, whether proposed by F tima or some
 other source such as Garabandal, Medjugorje or another, without
 fear, that is, with complete confidence in God's providence for us
 and the world. The future will take care of itself if we remain
 spiritually prepared for anything. This has always been the advice
 of the saints, anyway.