‘I think, too, that these locutions have done your soul good, and in particular that they have made you see your own wretchedness and your faults more clearly, and amend them.
They have lasted long, and always with spiritual profit. They move you to love God, and to despise yourself, and to do penance.
I see no reasons for condemning them, I incline rather to regard them as good, provided you are careful not to rely altogether on them, especially if they are unusual, or bid you do something out of the way, or are not very plain.
In all these and the like cases you must withhold your belief in them, and at once seek for direction. . . Also it should be considered that, even if they do come from God, Satan may mix with them suggestions of his own; you should therefore be always suspicious of them.
Also, when they are known to be from God, men must not rest much on them, seeing that holiness does not lie in them, but in a humble love of God and our neighbour; everything else, however good, must be feared, and our efforts directed to the gaining of humility, goodness, and the love of our Lord.
It is seemly, also, not to worship what is seen in these visions, but only Jesus Christ, either as in Heaven or in the Sacrament, or, if it be a vision of the Saints, then to lift up the heart to the Holy One in Heaven, and not to that which is presented to the imagination: let it suffice that the imagination may be made use of for the purpose of raising me up to that which it makes me see.’
Wisdom and prayers of saints 