The reference is clearly to those who should thus go to impart knowledge; to give information; to call the attention of men to great and important matters.
The language is applicable to any methods of imparting important knowledge, and it refers to a time when this would be the characteristic of the age.
There is nothing else to which it can be so well applied as to the labors of Christian missionaries, and ministers of the gospel, and others who, in the cause of Christian truth, go about to rouse the attention of men to the great subjects of religion; and the natural application of the language is to refer it to the times when the gospel would be preached to the world at large.
And knowledge shall be increased - To wit, by this method. The angel seems to mean that in this way there would be an advance in knowledge on all the subjects of religion, and particularly on the points to which he had referred. This would be one of the characteristics of these times, and this would be the means by which it would be accomplished. Our own age has furnished a good illustration of the meaning of this language, and it will be still more fully and strikingly illustrated as the time approaches when the knowledge of the Lord shall fill the whole world.
Many shall endeavour to search out the sense; and knowledge shall be increased by these means; though the meaning shall not be fully known till the events take place: Then the seal shall be broken, and the sense become plain. This seems to be the meaning of this verse, though another has been put on it, viz., "Many shall run to and fro preaching the Gospel of Christ, and therefore religious knowledge and true wisdom shall be increased." This is true in itself; but it is not the meaning of the prophet's words.
towards the end of the time appointed, many persons will be stirred up to inquire into these things delivered in this book, and will spare no pains or cost to get knowledge of them; will read and study the Scriptures, and meditate on them; compare one passage with another; spiritual things with spiritual, in order to obtain the mind of Christ; will peruse carefully the writings of such who have gone before them, who have attempted anything of this kind; and will go far and near to converse with persons that have any understanding of such things: and by such means, with the blessing of God upon them, the knowledge of this book of prophecy will be increased; and things will appear plainer the nearer the accomplishment of them is; and especially when accomplished, when prophecy and facts can be compared together: and not only this kind of knowledge, but knowledge of all spiritual things, of all evangelic truths and doctrines, will be abundantly enlarged at this time; and the earth will be filled and covered with it, as the sea with its waters; see Isaiah 11:9.