Genevieve Lloyd, in Spinoza and the Idea of the Secular, Mededelingen vanwege het Spinozahuis, Voorschoten 2013:

Spinoza saw the belief in immortality not as merely irrelevant to morals but as an obstancle to true virtue. For him, the dread of punishment after death was not just an inadequate basis for virtue; it was inimical to it. Virtue not only does not depend on the belief in an after-life; it depends on the rejection of that belief. In this respect, his approach to virtue echoes the ancient Epicurean/Lucretian philosophy. His rich but mystifying articulation of the eternity of the mind, in Part Five of the Ethics – whatever we make of it – is clearly not an orthodox doctrine of continued existence after bodily death, in any form which would allow for susceptibility to punishment or reward. For the basis of human well-being and virtue, Spinoza looked, not to an after-life, but to the joy associated in the present life with the love of a God who does not transcend Nature.

Spinoza was strongly committed to the rejection of the after-life; but he also passionately believed that the common perception of him as an ‘atheist’ was deeply, dangerously, misconstrued. It is in the striking conjunction of those two concerns – to reject prevailing beliefs in the after-life and to repudiate the perception of his philosophy as involving atheism – that we see most clearly how he prepared the way for the modern idea of the secular.

There is on the face of it something puzzling here. From our own temporal perspective – in the light of the connotations ‘atheism’ now has – Spinoza seems clearly to qualify as an atheist: he rejects the belief in a transcendent God, the belief in the supernatural. Yet I think it is also clear that he is genuine in his vehement rejection of the ‘atheist’ label. To see what is at stake here, I want now to look at some significant portions of his correspondence [not included here], which indicate, not only that he did not regard himself as an atheist, but that he thought that misconception threatened what he saw as the very core of his philosophy. He was deeply concerned about the imputation of atheism – not only fot he sake of his reputation, but fot the sake of the right understanding of what he describes as the ‘true philosophy’ for which he lived.