Good afternoon. Your question was answered by Gottfried Leibniz in his magnificent work Monadology. I do not speak English very well, so I apologise in advance for any inaccuracies in my answer. The reasoning is as follows:
"37. And since all this multifariousness conceals in itself only other accidents, preceding or still more complex and multifarious, of which each, in order to find a foundation for it, requires the same analysis, we shall not move further in this respect, and consequently the sufficient, or last, foundation must stand outside the chain, or series, of this multifariousness of accidental things, however infinite the series may be.
38. Thus the final cause of things must be in a necessary substance, in which the manifoldness of change is in a superior degree, as in a source; and this we call God.
39. And since this substance is the sufficient ground for all this diversity, which is everywhere in mutual connection, there is only one God, and this God is sufficient.
39. And since this substance is the sufficient ground for all this diversity, which is everywhere in mutual connection, there is only one God, and this God is sufficient.
40. Hence we may conclude that this supreme substance, which is one, universal, and necessary, since there is nothing outside of it that is independent of it, and since it is the mere consequence of possible being, must be unattached to limits and contain as much reality as is possible.
41. Hence it is evident that God is absolutely perfect, since perfection is nothing else than the magnitude of positive reality taken in the strict sense, without those limits, or boundaries, which consist in the things possessing it. And where there are no limits, i.e., in God, perfection is absolutely infinite.
42. Hence it follows also that creatures have their perfections from the influence of God, but that they have their imperfections from their own nature, which is incapable of being without bounds. For it is by this that they differ from God. This original imperfection of creatures is noticeable in the natural inertia of bodies.
43. It is also true that in God lies the source not only of existences, but also of essences, since they are real, or the source of all that is real in possibility. And this is because the mind of God is the domain of the eternal truths, or ideas, on which these truths depend, and without him there would be not only nothing existing, but even nothing possible.
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48. In God consists power, which is the source of all things, then knowledge, which contains all the diversity of ideas, and finally the will, which produces changes or creatures according to the beginning of the best. And this corresponds to what in the created monads constitute the subject, or ground, the faculty of perception and the faculty of striving. But in God these attributes are certainly infinite or perfect, while in the created monads, or entelechies (perfectihabies), as Hermolaus Barbarus translated the word, are only imitations in so far as the monads have perfections."