But turned back ... - See the notes at Psalm 78:41.

They were turned aside like a deceitful bow - literally, a bow of deceit. That is, a bow that could not be depended on; a bow, one of whose arms was longer or more elastic than the other, so that the arrow would turn aside from the mark. The marksman would attempt to hit an object, and would fail. So it was with the people of Israel. They could not be depended on. No reliance could be put on their promises, their covenant-engagements, their attachment, their fidelity, for in these things they failed, as the arrow from a deceitful bow would fail to strike the mark. Their whole history shows how just was this charge; alas! the history of many of the professed people of God has shown how applicable the description has been to them also.

They were turned aside like a deceitful bow - The eastern bow, which when at rest is in the form of a [curved figure], must be recurved, or turned the contrary way, in order to be what is called bent and strung. If a person who is unskilful or weak attempt to recurve and string one of these bows, if he take not great heed it will spring back and regain its quiescent position, and perhaps break his arm. And sometimes I have known it, when bent, to start aside, and regain its quiescent position, to my no small danger, and in one or two cases to my injury. This image is frequently used in the sacred writings; but no person has understood it, not being acquainted with the eastern bow [curved figure], which must be recurved, or bent the contrary way, [figure] in order to be proper for use. If not well made, they will fly back in discharging the arrow. It is said of the bow of Jonathan, it turned not back, 2 Samuel 1:22, לא נשוג אחור lo nasog achor, "did not twist itself backward." It was a good bow, one on which he could depend. Hosea, Hosea 7:16, compares the unfaithful Israelites to a deceitful bow; one that, when bent, would suddenly start aside and recover its former position. We may find the same passage in Jeremiah 9:3. And this is precisely the kind of bow mentioned by Homer, Odyss. xxi., which none of Penelope's suitors could bend, called καμπυλα τοξα and αγκυλα τοξα, the crooked bow in the state of rest; but τοξον παλιντονον, the recurred bow when prepared for use. And of this trial of strength and skill in the bending of the bow of Ulysses, none of the critics and commentators have been able to make any thing, because they knew not the instrument in question. On the τοξου θησις of Homer, I have written a dissertation elsewhere. The image is very correct; these Israelites, when brought out of their natural bent, soon recoiled, and relapsed into their former state.

But turned back,.... From God and his worship, apostatized from the true religion, and turned to idols:

and dealt unfaithfully, like their fathers; in the wilderness; see Psalm 78:8,

they were turned aside like a deceitful bow; that promises well to carry the arrow right, but drops it at the feet of the archer; or carries it another way, so that it misses the mark, The Targum is,

"as a bow casting arrows;''

to the ground, and not to the mark; see Hosea 7:16, or being too much stretched is suddenly broken, and kills the archer; or returns to its own nature; so Arama.

But turned back, and dealt {i} unfaithfully like their fathers: they were turned aside like a deceitful bow.

(i) Nothing more displeases God in the children, than when they continue in that wickedness, which their fathers had begun.

78:57 Deceitful bow - Which either breaks when it is drawn, or shoots awry, and frustrates the archer's expectation.

78:56-72 After the Israelites were settled in Canaan, the children were like their fathers. God gave them his testimonies, but they turned back. Presumptuous sins render even Israelites hateful to God's holiness, and exposed to his justice. Those whom the Lord forsakes become an easy prey to the destroyer. And sooner or later, God will disgrace his enemies. He set a good government over his people; a monarch after his own heart. With good reason does the psalmist make this finishing, crowning instance of God's favour to Israel; for David was a type of Christ, the great and good Shepherd, who was humbled first, and then exalted; and of whom it was foretold, that he should be filled with the Spirit of wisdom and understanding. On the uprightness of his heart, and the skilfulness of his hands, all his subjects may rely; and of the increase of his government and peace there shall be no end. Every trial of human nature hitherto, confirms the testimony of Scripture, that the heart is deceitful above all things, and desperately wicked, and nothing but being created anew by the Holy Ghost can cure the ungodliness of any.