According to Spinoza, there is only one substance, which is God. Divine substance is free because it exists in accordance with its own nature; it is eternal, because the existence lies in its essence. In accordance with Lin, Spinoza holds a number of highly controversial theses concerning God. All this is contained in the eight definitions of "Ethics" of Spinoza, and the conclusion is that God is the only existing substance, because " All things were created by Him, and apart from Him not one thing was created" as well as "Everything that happens, happens only by the laws of the infinite divine nature and consequence of its essential nature". Obviously, with this formulation, the problem of proving the existence of God can be a variation of the ontological argument. It is impossible to think of God (or substance) as a "cause of itself," apart from its inevitable existence. According to Spinoza’s hypothesis God is the creation, in whose existence people are sure more than in anything else. Spinoza's God is God of the Bible. He is not the personal God with the will and mind. Spinoza believed that perceiving God as a person would make Him anthropomorphic. What is more, the philosopher proves that God is "immanent", therefore, He can not be separated from the things coming from him. He is not Providence in the traditional sense but presents impersonal absolute necessity. In the necessity of God, Spinoza found what he was looking for: the essence of all certainty, proof of all, the source of the highest peace and tranquility. Naturally, it should make sure that God, who gives the philosopher limitless peace is God who is expressed in geometric patterns of Spinoza’s Ethics.
The content of faith (whether in Old or New Testament) is reduced to a few basic provisions that Spinoza formulates in seven points. Firstly, God is an extremely fair and compassionate being, a sample of real life. Someone who does not know about Him or do not believe in His existence can neither obey nor recognize His righteous judgment. Secondly, God is the one. No one can doubt that the acceptance of this dogma is required for complete devotion, admiration of God, because only devotion, admiration and love beget His exceptional superiority over all others. The third point states, that God is omnipresent, that is, He knows everything. Believing that it can be anything to hide from Him, would be to doubt the validity of his justice, according to which he controls everything. The next point is that God has the supreme right and power over all and acts and not by virtue of any law, but according to his absolute will and the power of his exceptional grace. Everyone is obliged to obey. The fifth point proclaims that worship and obedience to God is in justice and humanity that is, in love for neighbor. The next point said that all who are obedient to God during life will be saved; the rest who live by the power of instincts will die. The last point confessed that God forgives the sins of those who repent. It is true that all people fall into sin; if there was no certainty of forgiveness, people would lose the hope for salvation, and then there would be no reason to consider God merciful.
Speaking about value of Spinoza’s works Jousse stated, it seems obvious that Spinoza’s God in spite of his historical and intellectual influences, can be applied to our world and could really improve it by solving its excesses. But how it is possible? All the definition of God has been built with reason, so God’s idea in our world has to be introduced with reason, and, as a consequence, by education. That is why it is so important to learn to young people how to think and how to grasp these metaphysical problems.
As well as Spinoza, Leibniz based his philosophy on the concept of "substance", but it is radically different from the Spinoza’s ethics in consideration of the relation of mind and matter, and in consideration of the number of substances.
In opposition to Spinoza, Leibniz permits the presence of free will in his system. He puts forward the "principle of sufficient reason", according to which nothing happens without a reason, but when dealing with free factors, the reasons for their actions are the “propensity without necessity.”
Every human act is always motivated, but there is no logical need for a reasonable basis for its action. Leibniz says so at least when he writes for the general reader, but, as one can learn, Leibniz has also another theory, which he hid after he learned that it was outraged by Arno. Leibniz agrees with Thomas Aquinas that God can not act contrary to the laws of logic, but He may enjoin all that is logically possible, and this gives him the greatest breadth of choice. Leibniz gives metaphysical proofs of God's existence in their complete form. In his famous work The Principles of Philosophy known as Monadology Leibniz states, “We may also hold that this supreme substance, which is unique, universal and necessary, nothing outside of it being independent of it,- this substance, which is a pure sequence of possible being, must be illimitable and must contain as much reality as is possible.” Sometimes, in order to describe his transcendent God the philosopher uses the phrase “supra-mundane intelligence”.
In conclusion, it should be said that the concept of God of these two talented philosophers goes back to one simple question; who is God? Does God have any choice? Leibniz proves that God have the choice; Spinoza proclaims the opposite. It should be said that Spinoza’s Substance exists well beyond the merely human categories such as evil and good. Leibniz argues that God is transcendent while Spinoza believes that God is immanent. Spinozistic and Leibnizian conceptions of divinity are extremely helpful for modern scientists.