The entrance of thy word is light. The amount is, that the light of the truth revealed in God's word, is so distinct that the very first sight of it illuminates the mind. The word phtch pethach, properly signifies an opening, [1] but metaphorically it is taken for a gate. Accordingly the old translator has rendered it beginning, which is not improper, provided it is understood of the rudiments or first elements of the divine law. It is as if the Prophet had -- "Not only do those who have attained an accurate acquaintance with the whole law, and who have made the study of it the business of their lives, discern there a clear light, but also those who have studied it even very imperfectly, and who have only, so to speak, entered the porch." Now we must reason from the less to the greater. If tyroes and novices begin to be enlightened at their first entrance, what will be the case when a man is admitted to a full and perfect knowledge? In the second clause the Prophet unfolds his meaning more fully. By little ones he denotes such as neither excel in ingenuity nor are endued with wisdom, but rather are unskilled in letters, and unrefined by education. Of such he affirms that, as soon as they have learned the first principles of the law of God, they will be endued with understanding. It ought to have a most powerful influence in exciting in us an earnest desire to become acquainted with the law of God, when we are told that even those who, in the estimation of the world, are fools, and contemptible simpletons, provided they apply their minds to this subject, acquire from it wisdom sufficient to lead them to eternal salvation. Although it is not given to all men to attain to the highest degree in this wisdom, yet it is common to all the godly to profit so far as to know the certain and unerring rule by which to regulate their life. Thus no man who surrenders himself to the teaching of God, will loose his labor in his school, for from his first entrance he will reap inestimable fruit. Meanwhile we are warned, that all who follow their own understanding, wander in darkness. By affirming that the little ones are enlightened, David intimates, that it is only when men, divested of all self confidence, submit themselves with humble and docile minds to God, that they are in a proper state for becoming proficient scholars in the study of the divine law. Let the Papists mock, as they are accustomed to do, because we would have the Scriptures to be read by all men without exception; yet it is no falsehood which God utters by the mouth of David, when he affirms that the light of his truth is exhibited to fools. God will not, therefore, disappoint the desire of such as acknowledge their own ignorance, and submit themselves humbly to his teaching.

Footnotes

1 - "phth pethach, the opening of thy words giveth light:' when I open my Bible to read, light springs up in my mind." -- Dr. Adam Clarke. The corresponding word in Syriac signifies to enlighten, and in Arabic to explain. Hence, in the opinion of some, phtch, pethach, is the expounding of thy word.

The entrance of thy words giveth light - The Septuagint translates this, "the manifestation (or declaration) - ἡ δήλωσις hē dēlōsis - of thy words enlightens." So the Vulgate. Luther renders it, "When thy word is revealed, so it delivers us, and makes the simple wise." DeWette, "The opening (revelation) of thy word," etc. The Hebrew word - פתח pethach - means an "opening" or "entrance" - as of a gate, Joshua 20:4; Judges 9:35; and then "a door," as of a tent or the temple, Genesis 18:1; 1-Kings 6:8; or the gate of a city, Isaiah 3:26; and then it means opening, insight, instruction. The word as used here seems to denote the opening or unfolding of the word of God; the revelation of that word to the mind. A door is open so that we enter into a house; a gate, so that we enter into a city; and thus the meaning of the word of God is "opened" to us, so that we may, as it were, enter in and see its beauty. The language does not, therefore, denote the entrance of that word into the mind, but, its being made open to us so that we may perceive its beauty, or may ourselves "enter" into its meaning, its mysteries, and its beauties.
It giveth understanding unto the simple - The word rendered "simple" literally means "those who are open to persuasion," or who are easily enticed or seduced. Then it refers to the credulous, Proverbs 14:15, and then to the "inexperienced." See Psalm 19:7, note; Psalm 116:6, note.

The entrance of thy words giveth light - פתח pethach, the opening of it: when I open my Bible to read, light springs up in my mind. Every sermon, every prayer, every act of faith, is an opening by which light is let into the seeking soul.

The entrance of thy (b) words giveth light; it giveth understanding unto the simple.
(b) The simple idiots that submit themselves to God have their eyes opened and their minds illuminated, as soon as they begin to read God's word.

The entrance of thy words giveth light,.... The beginning of them; the first three chapters in Genesis, what light do they give into the origin of all things; the creation of man, his state of innocence; his fall through the temptations of Satan, and his recovery and salvation by Christ, the seed of the woman, the first principles of the oracles of God, the rudiments of religion, the elements of the world, the rites of the ceremonial law, gave great light into Gospel mysteries. As soon as a man enters upon reading the Scriptures, if he has any degree of understanding of the things in them, they immediately throw light into his mind; or, however, as soon as ever the word has an entrance into the heart, and through the Spirit, power, and grace of God, makes its way and has a place there, that being opened by the Lord for that purpose, light arises in darkness. It maybe rendered, "the opening of thy words giveth light" (p); and may signify either the interpretation and explanation of the word of God by the ministers of it, which is often of singular use for enlightening and warming the hearts of men, Luke 24:32; and to this sense are the Vulgate Latin and Septuagint versions; the one rendering it "the declaration of thy words", the other, "the manifestation" of them; and so the Ethiopic and Arabic versions; and to this sense is the Targum;
"the impression of thy words will enlighten those that are dark.''
Or it may intend the word that opens, as well as is opened, since it is the means of opening blind eyes; and so giving light to men to see their lost state by nature, and the suitableness of Christ as a Saviour, his fulness and grace, ability and willingness; to behold the wondrous things of the Gospel, the way they should walk in, and the duties of religion they should perform;
it giveth understanding unto the simple: who want understanding in the knowledge of divine and spiritual things, as all men do; and who are sensible of their want of it, ingenuously confess it, and are meek and humble; and so not above instruction, as proud and conceited persons are. Some render it "babes" (q); and it may design such who are but of weak parts, in comparison of others, to whom the things of the Gospel are revealed, when they are hid from the wise and prudent: Christ by his Spirit opens their understandings, that they may understand the Scriptures; and by means of them gives them an understanding of himself, and of those things which make them wise unto salvation, and make for their spiritual peace and comfort, and their eternal welfare; see Psalm 19:7.
(p) "apertio", Pagninus, Montanus, Musculus, Vatablus, Michaelis; "apertura", Cocceius, Gejerus; so Ainsworth. (q) Sept. "parvulis", V. L. so Arab. Ethiop. Musculus.

The entrance--literally, "opening"; God's words, as an open door, let in light, or knowledge. Rather, as HENGSTENBERG explains it, "The opening up," or, "explanation of thy word." To the natural man the doors of God's Word are shut. Luke 24:27, Luke 24:31; Acts 17:3; Ephesians 1:18, confirm this view, "opening (that is, explaining) and alleging," &c.
unto the simple--those needing or desiring it (compare Psalm 19:7).