I am the Lord thy God ... - See Exodus 20:2. The meaning is, "I am Yahweh, that God; the God to be worshipped and honored by thee; I only am thy God, and no other god is to be recognized or acknowledged by thee." The foundation of the claim to exclusive service and devotion is here laid in the fact that he had brought them out of the land of Egypt. Literally, had caused them to ascend, or go up from that land. The claim thus asserted seems to be twofold:
(a) that in doing this, he had shown that he was God, or that he had performed a work which none but God could perform, and had thus shown his existence and power; and
(b) that by this he had brought them under special obligations to himself, inasmuch as they owed all that they had - their national existence and liberty - entirely to him.
Open thy mouth wide, and I will fill it - Possibly an allusion to young birds, when fed by the parent-bird. The meaning here is, "I can amply supply all your needs. You need not go to other gods - the gods of other lands - as if there were any deficiency in my power or resources; as if I were not able to meet your necessities. All your needs I can meet. Ask what you need - what you will; come to me and make any request with reference to yourselves as individuals or as a nation - to this life or the life to come - and you will find in me all abundant supply for all your needs, and a willingness to bless you commensurate with my resources." What is here said of the Hebrews may be said of the people of God at all times. There is not a want of our nature - of our bodies or our souls; a want pertaining to this life or the life to come - to ourselves, to our families, to our friends, to the church, or to our country - which God is not able to meet; and there is not a real necessity in any of these respects which he is not willing to meet. Why, then, should his people ever turn for happiness to the "weak and beggarly elements of the world" (compare the notes at Galatians 4:9), as if God could not satisfy them? Why should they seek for happiness in vain amusements, or in sensual pleasures, as if God could not, or would not, supply the real needs of their souls?
Clarke's Commentary on the Bible
Open thy mouth wide - Let thy desires be ever so extensive, I will gratify them if thou wilt be faithful to me. Thou shalt lack no manner of thing that is good.
Gill's Exposition of the Entire Bible
I am the Lord thy God,.... The true Jehovah, the Being of beings, in whom all live and move and have their beings, the covenant God of his people; and is a reason why they should hear him, and worship him, and no other:
which brought thee out of the land of Egypt; this, with what goes before, is the preface to the ten commands, the first and principal of which is urged in the preceding verse; and this is another reason why the Lord God should be had and worshipped, and not a strange god; and redemption from worse than Egyptian bondage, from the bondage of sin, Satan, and the law, and a deliverance from worse than Egyptian darkness, and from a state of wickedness and impiety, should lay under greater obligations still to serve the Lord, and worship him only; who adds, as a further reason for it,
open thy mouth wide, and I will fill it; which may be understood of opening the mouth either in prayer or in praise: to open the mouth wide in prayer is to pray with great freedom, to pour out the soul to God, lay open its whole case, and tell him all his mind and wants; to pray with great boldness, and with much importunity and fervency, and in full assurance of faith, pleading with great strength the promises of God, and asking in faith for much, according to them; and God may be said to fill this wide mouth of faith in prayer, when he grants the desires of the heart, gives his people what they will, even very largely and abundantly, yea, more than they can ask or think: to open the mouth wide in praise is to be abundantly thankful for mercies received; and when persons are so, the Lord fills them with more abundant matter for praise and thanksgiving; see Psalm 71:8, or this may be interpreted of opening the mouth wide in expressions of desire after spiritual food, hungering and thirsting after spiritual things, when the Lord fills or satisfies the mouths of his people with good things, Psalm 103:5, with the sincere milk of the word which they desire, and with the ordinances, the breasts of consolation they long for, and so satisfies them with the goodness and fatness of his house, Psalm 64:4, the metaphor seems to be taken from the young of birds, which open their mouths, and are filled by the old ones: the Targum is,