I am the LORD thy God, which brought thee out of the land of Egypt: {i} open thy mouth wide, and I will fill it.

(i) God accuses their incredulity, because they did not open their mouths to receive God's benefits in such abundance as he pours them out.

Wesley's Notes

81:10 Wide - Either to pray for mercies, or to receive the mercies which I am ready to give you.

Matthew Henry's Concise Commentary

81:8-16 We cannot look for too little from the creature, nor too much from the Creator. We may have enough from God, if we pray for it in faith. All the wickedness of the world is owing to man's wilfulness. People are not religious, because they will not be so. God is not the Author of their sin, he leaves them to the lusts of their own hearts, and the counsels of their own heads; if they do not well, the blame must be upon themselves. The Lord is unwilling that any should perish. What enemies sinners are to themselves! It is sin that makes our troubles long, and our salvation slow. Upon the same conditions of faith and obedience, do Christians hold those spiritual and eternal good things, which the pleasant fields and fertile hills of Canaan showed forth. Christ is the Bread of life; he is the Rock of salvation, and his promises are as honey to pious minds. But those who reject him as their Lord and Master, must also lose him as their Saviour and their reward.