It is well known that in Genesis the Greek word logos means 'discourse' or 'word', but there is an old sense of logos that allows it to be linked to the concept of 'number'. To recover it, Paolo Zellini traces through the texts how close they were to word and number in our tradition and discovers that the term logos combined both senses already in the verses of Homer, as well as in the early theogonies, in the ancient tragedy and in the Pythagorean philosophy. Likewise, in the sources that attest to the ritual origin of mathematics, the number has a similar meaning to that which the logos in Christianity later acquire. Thanks to the study of these concepts we will understand the origin and destiny of the philosophical and scientific thought of the West: to think the logos does not suppose the vague evocation of myths and remote traditions, but it allows to reconstruct the common root of the knowledge before the division between the letters and the sciences.