To understand what Hosea meant by knowledge we must examine the singularly supple word which his language lent him to express it. The Hebrew root "Yadh'a,"[673] almost exclusively rendered in the Old Testament by the English verb to know, is employed of the many processes of knowledge, for which richer languages have separate terms. It is by turns to perceive, be aware of, recognise, understand or conceive, experience and be expert in.[674] But there is besides nearly always a practical effectiveness, and in connection with religious objects a moral consciousness.
The barest meaning is to be aware that something is present or has happened, and perhaps the root meant simply to see.[675] But it was the frequent duty of the prophets to mark the difference between perceiving a thing and laying it to heart. Isaiah speaks of the people _seeing_, but not so as _to know_;[676] and Deuteronomy renders the latter sense by adding _with the heart_, which to the Hebrews was the seat, not of the feeling, but of the practical intellect:[677] _And thou knowest with thy heart that as a man chastiseth his son, so the Lord your God chastiseth you_.[678] Usually, however, the word _know_ suffices by itself. This practical vigour naturally developed in such directions as _intimacy_, _conviction_, _experience_ and _wisdom_. Job calls his familiars _my knowers_;[679] of a strong conviction he says, _I know that my Redeemer liveth_,[680] and referring to wisdom, _We are of yesterday and know not_;[681] while Ecclesiastes says, _Whoso keepeth the commandment shall know_--that is, _experience_, or _suffer--no evil_.[682] But the verb rises into a practical sense--to the knowledge that leads a man to regard or care for its object. Job uses the verb _know_ when he would say, _I do not care for my life_;[683] and in the description of the sons of Eli, that _they were sons of Belial, and did not know God_, it means that they did not have any regard for Him.[684] Finally, there is a moral use of the word in which it approaches the meaning of conscience: _Their eyes were opened, and they knew that they were naked_.[685] They were aware of this before, but they felt it now with a new sense. Also it is the mark of the awakened and the fullgrown to know, or to feel, the difference between good and evil.[686]
Here, then, we have a word for _knowing_, the utterance of which almost invariably starts a moral echo, whose very sound, as it were, is haunted by sympathy and by duty. It is knowledge, not as an effort of, so much as an effect upon, the mind. It is not _to know_ so as to see the fact of, but _to know_ so as to feel the force of; knowledge, not as acquisition and mastery, but as impression, passion. To quote Paul's distinction, it is not so much the apprehending as the being apprehended. It leads to a vivid result--either warm appreciation or change of mind or practical effort. It is sometimes the talent conceived as the trust, sometimes the enlistment of all the affections. It is knowledge that is followed by shame, or by love, or by reverence, or by the sense of a duty. One sees that it closely approaches the meaning of our "conscience," and understands how easily there was developed from it the evangelical name for repentance, Metanoia--that is, change of mind under a new impression of facts.
There are three writers who thus use knowledge as the key to the Divine life--in the Old Testament Hosea and the author of Deuteronomy, in the New Testament St. John. We likened Amos to St. John the Baptist: it is not only upon his similar temperament, but far more upon his use of the word knowledge for spiritual purposes, that we may compare Hosea to St. John the Evangelist.