There is a passage[1] in Locke's Essay Concerning Humane Understanding of which I took special note from the first time that I read it:

5. That men should keep their compacts is certainly a great and undeniable rule in morality. But yet, if a Christian, who has the view of happiness and misery in another life, be asked why a man must keep his word, he will give this as a reason:—Because God, who has the power of eternal life and death, requires it of us. But if a Hobbist be asked why? he will answer:—Because the public requires it, and the Leviathan will punish you if you do not. And if one of the old philosophers had been asked, he would have answered:—Because it was dishonest, below the dignity of a man, and opposite to virtue, the highest perfection of human nature, to do otherwise.

The reason that this passage stood-out and stands-out for me is that it contains a fundamentally sympathetic statement of a godless morality, and indeed fairly clearly exhibits the parallel between the might of G_d making ostensible right for the Christian, and the might of the State making ostensible right for the Hobbsean.[2] Locke's philosophy, epistemological and ethical, is heavily informed by a belief in a loving G_d, yet here Locke seems to reveal sufficient subtlety to do rather well without that G_d.

There's another striking passage[3] in that same work:

50. If we look upon those superior beings above us, who enjoy perfect happiness, we shall have reason to judge that they are more steadily determined in their choice of good than we; and yet we have no reason to think they are less happy, or less free, than we are. And if it were fit for such poor finite creatures as we are to pronounce what infinite wisdom and goodness could do, I think we might say, that God himself cannot choose what is not good; the freedom of the Almighty hinders not his being determined by what is best.

51. A constant determination to a pursuit of happiness no abridgment of liberty. But to give a right view of this mistaken part of liberty let me ask,—Would any one be a changeling, because he is less determined by wise considerations than a wise man? Is it worth the name of freedom to be at liberty to play the fool, and draw shame and misery upon a man's self? If to break loose from the conduct of reason, and to want that restraint of examination and judgment which keeps us from choosing or doing the worse, be liberty, true liberty, madmen and fools are the only freemen: but yet, I think, nobody would choose to be mad for the sake of such liberty, but he that is mad already. The constant desire of happiness, and the constraint it puts upon us to act for it, nobody, I think, accounts an abridgment of liberty, or at least an abridgment of liberty to be complained of. God Almighty himself is under the necessity of being happy; and the more any intelligent being is so, the nearer is its approach to infinite perfection and happiness. That, in this state of ignorance, we short-sighted creatures might not mistake true felicity, we are endowed with a power to suspend any particular desire, and keep it from determining the will, and engaging us in action. This is standing still, where we are not sufficiently assured of the way: examination is consulting a guide. The determination of the will upon inquiry, is following the direction of that guide: and he that has a power to act or not to act, according as such determination directs, is a free agent: such determination abridges not that power wherein liberty consists. He that has his chains knocked off, and the prison doors set open to him, is perfectly at liberty, because he may either go or stay, as he best likes; though his preference be determined to stay, by the darkness of the night, or illness of the weather, or want of other lodging. He ceases not to be free; though the desire of some convenience to be had there absolutely determines his preference, and makes him stay in his prison.

Now, regardless of whether we agree that a being can be free and yet determined by something (not, as I believe, a contradiction if that something is internalized in the determined being), the fact remains that a G_d of this sort is more law-driven than many would conceive G_d to be.

Anyway, what brings all this to mind is that, lately, I have been reading (albeït in somewhat desultory manner) The Courtier and the Heretic: Leibniz, Spinoza, and the Fate of God in the Modern World by Matthew Stewart. Chapter 15 (The Haunting) contains a section entitled Stopping Locke, which ends thus

Locke's vague conjecture that matter might be able to think, of course, is Spinoza's avowed doctrine. […] Leibniz's magesterial refutation of the founder of British empiricism, in brief, is a covert assault [Spinoza]. Furthermore, [in Leibniz's mind] Locke — like Descartes before him — is really just a feeble imitation of Spinoza: he leaves in doubt that which his dark master pitilessly destroys.

[…]

Leibniz's unstated intuition that Locke was something of a Spinozist, incidentally, is probably more insightful than is generally allowed in modern interpretations of the great empiricist's work. Locke wrote much of his Essay while living in exile in Holland from 1683 to 1688, during which time he purchased all of Spinoza's works and mingled in circles that included some suspiciously freethinking characters. Furthermore, the parallels between his work and that of Spinoza extend well beyond those suggested by Leibniz. To be sure, as a conciliation-minded member of the Christian establishment, Locke toned down or obfuscated some of the more radical implications of his Spinozism — a task for which his inimitably wobbly prose was particularly well suited.

I would hardly agree that Locke's prose were wobbly, let alone that it were inimitably so; in fact, I don't think that a person given to wobbly writing would be capable of the sort of perspicacious thinking that got Locke as far along as his did. But the point remains that some of what I noted in Locke, such as in the two paragraphs of the Essay that I quoted, demonstrates that Locke represented some of the same tendencies as did Spinoza. Any notion that Locke borrowed heavily from Spinoza would have to confront what was already indicated by Locke's background and writings before he fled to Holland (and, earlier, before Spinoza had published anything); none-the-less, it would hardly be surprising if Leibniz indeed feared that Locke were in effect an agent of Spinoza's philosophy.

[1] Book I Chapter II ¶5, in the 1894 edition edited by Alexander Campbell Fraser (which is the edition that I read).

[2] The Hobbsean will assert that the State makes possible a manner of living whose goodness is not itself derived from the dictates of the State. Many Christians would want to make a similar claim for the goodness of the manner of living made possible by G_d. However, if pressed, most of them would not answer as did Ευθύφρων in the fable by the old philosopher Πλάτων; rather, they would feel compelled to hold that not simply instances of goodness but the distinction of goodness were creäted by the power of G_d. But Locke himself proves an apparent exception to my characterization. (See above.)

[3] Book II Chapter XXI ¶50-1.