Der freie Mensch denkt über nichts weniger nach als über den Tod: seine Weisheit ist nicht ein Nachsinnen über den Tod, sondern über das Leben. - Benedictus de Spinoza

Spinoza did not envision secular Judaism. To be a secular or assimilated Jew is, in his view, nonsense. It is to be a nonsectarian sectarian. For him, Judaism without an observance of its textually and historically defined tenets, laws, and ceremonies would be a masquerade. [...] Of course, Spinoza had great contempt for traditional sectarian religions, and Judaism in particular. And he did argue that Jewish law is no longer binding on contemporary Jews. Perhaps in this sense he unwittingly opened the door for a secular or even Reform Judaism. But he also had a very strict understanding of what was to count as Judaism. Spinoza may have been a religious reformer, but what he envisioned was not reform within Judaism. Rather, what he had in mind was a universal rational religion that eschewed meaningless, superstitious rituals and focused instead on a few simple moral principles, above all, to love one's neighbor as oneself.

that the foundation of all good and evil is love falling on a certain object. For whenever we do not love that object which alone is worthy of being loved, i.e. God, there follow necessarily from that hate and sadness.

According to the seventeenth-century way of thinking, an atheist was by definition a decadent. If there was no God (or, at least, no providential, rewarding-and-punishing God of the sort worshipped in all the traditional religions), the reasoning went, then everything is permitted. So a non-beliver would be expected to indulge in all manner of sensual stimulation... to lie, cheat, and steal...
Spinoza, according to all seventeenth-century interpreters, rejected all the traditional ideas about God; he was indesputably a heretic. Yet his manner of living was humble and apparently free of vice. Then, as now, the philosopher seemed a living oxymoron: he was an ascetic sensualist, a spiritual materialist, a sociable hermit, a secular saint. How could his life have been so good, the critics asked, when his philosophy was so bad?