The seven epistles are Christ’s messages of encouragement and warning, of praise and blame, which were given to John in vision, and which are addressed to the seven churches of proconsular Asia,(324) the scene of John’s later ministry, and through them to the church at large, for each epistle contains not only a message to the particular church, but “what the Spirit saith to [all] the churches”. The form of epistles or letters in an apocalypse was foreign to the Jewish method of writing, but was doubtless introduced by John because the use of such letters or epistles had already become established in the church as a characteristic expression of the Christian mind.(325) These seven churches were not the only ones then existing in Asia,(326) but were evidently chosen to represent them all, and were intended through their individual experience “to exemplify the experience of the whole church in the field of history”; not, however, in numerically successive and historic stages, but the general experience of the church universal throughout all time, for seven is the symbol of universality, and the seven churches are here intended to symbolize the universal church. Each of the seven churches named occupied a strategic point of special opportunity for gospel dispersion, and they were doubtless addressed for that reason, though the message imparted was divinely intended for the whole church in all the ages. The number seven occurs so often in the Revelation that it necessarily attracts our attention, and the book itself has not inaptly been styled “the Book of Sevens”. In each case, too, as here, the number has a symbolic reference, a fact that should not escape our observation, for it points the way to a general principle of interpretation, viz. that _every number used throughout the book, without exception, has an acquired symbolical meaning_,(327) i. e. its ordinary arithmetical value is ignored, or becomes subordinate, and it represents a different idea that has in some way become associated with it as a number; and this important consideration often furnishes a key to the correct interpretation. The origin of this symbolism is very early, antedating history—seven, for example, was a sacred number with the Accadian predecessors of the Semites in the remote dawn of Babylonian civilization.(328) This use probably had its rise from observations of the heavenly bodies, such as the phases of the moon lasting seven days, the seven planets of ancient astronomy, and the Pleiades, together with the occurrence of seven as a factor in gestation and in other well known phenomena, all of which served to impress upon the Eastern mind that the number was somehow inwrought in the order of nature and must therefore have a special significance. In a similar way the number ten probably had its origin as a symbol in the fact that it represented the complete number of digits on a man’s hands, and formed the norm of mathematical reckoning. Other numbers, also, from some real or fancied relation to things, became ready symbols for the Oriental mind. In the Apocalypse numbers are often introduced first in their ordinary significance, as the seven churches, and then pass easily and naturally to their symbolic meaning which is usually apparent. But it should be seen that a number does not thereby cease to have a quantitative value when it becomes symbolical, e. g. the seven churches represent a number still, though it is the number of all the churches, the whole church, and not seven units as before. It is the definite numerical value only that is lost in the symbolism, and not the entire idea of number or quantity; and the failure to recognize this fact may lead us astray in the interpretation, as for instance, in that of the thousand years in chapter twenty, where a great and complete number of years seems to be meant, and not the completeness of Satan’s binding apart from any period of time, as held by some commentators.(329)