Although our knowledge is finite and limited (because we are finite and limited creatures), God is said to be omniscient–he knows all things. Although we exercise creaturely power and freedom, God alone is properly said to be all-powerful and therefore sovereign over all things. Although we occupy both time and space, God transcends all such spatial and temporal limitations. He alone is omnipresent. Men and women can demonstrate goodness, love, mercy, etc., as a consequence of being created in the image of God, but he possesses these same attributes without limits or measure, unlike the way these attributes are manifest in us.
Much can be known about God from the created order. Through our interaction with the world around us, we know that God is eternal, all-powerful, and good (cf. Romans 1:20). Yet, whatever we learn about God through nature (general revelation), will always be limited by the character of revelation given through finite, created things. In addition, such revelation is inevitably corrupted by human sinfulness (Romans 1:21-25). Therefore, whatever sinful people learn about God through the natural order will be grossly distorted, and ironically, ends up serving as the basis for all forms of false religion and idolatry–a theme developed by the Apostle Paul in Romans 1:18-32. John Calvin was absolutely right when he spoke of the minds of sinful men and women as “idol factories” (Institutes, I.11.8). And it is because of this general revelation—the truth of which is suppressed in unrighteousness—that the entire human race stands condemned before God (Romans 1:20).
Since sinful human curiosity often leads to speculation about God’s hidden essence, it is important to remind ourselves that we can know nothing about God unless and until he condescends to reveal himself through the “two books” of nature and Scripture. In the Word of God, we find a number of divine “attributes” (or perfections) ascribed to God. So, rather than speculate about God’s hidden essence (which often ends up in idolatry), we must worship and serve God as he reveals himself to us through his Word. We can define these attributes as those perfections which are ascribed to God and which are evident in God’s works of creation, providence, and redemption.
Christian theologians have long struggled to explain how it is that certain of these divine perfections belong to God alone, while others are ascribed to humanity in finite measure since we are created in God’s image. The former attributes are most often identified as “incommunicable” attributes because these particular attributes cannot be “communicated” by God to his finite creatures. The latter are called “communicable” attributes because they are in fact communicated to humanity, though in finite measure due to our creaturely limitations, and understood primarily through analogy (i.e., God gives us examples in creation and his Word, which help us to better understand him).