The Scriptures which are current in the Churches of God do not speak of “seven” heavens, or of any definite number at all, but they do appear to teach the existence of “heavens,” whether that means the “spheres” of those bodies which the Greeks call “planets,” or something more mysterious. Celsus, too, agreeably to the opinion of Plato, asserts that souls can make their way to and from the earth through the planets; while Moses, our most ancient prophet, says that a divine vision was presented to the view of our prophet Jacob, — a ladder stretching to heaven, and the angels of God ascending and descending upon it, and the Lord supported upon its top—obscurely pointing, by this matter of the ladder, either to the same truths which Plato had in view, or to something greater than these. On this subject Philo has composed a treatise which deserves the thoughtful and intelligent investigation of all lovers of truth.
Source: Against Celsus (New Advent)