It is difficult to define God. We can come close by observing His qualities and His characteristics. When we try to describe a person to someone that they have never met, we refer to their eyes, hair, size and other characteristics. This is also how the Bible tells us about God. These are His known attributes:
God is omnipresent. This means that God is present everywhere at the same time (Jeremiah 23:23-34).
God is omniscient. In other words, He knows all things. He knows every thought and deed of man (Proverbs 15:3). He knows everything that takes place in nature, including even the death of a sparrow (Matthew 10:29). Though the universe is limitless and gloriously grand, He knows the eternal story of every grain of sand.
God is eternal. “Then Moses asked God, “If I go to the Israelites and say to them: The God of your fathers has sent me to you, and they ask me, ‘What is His name?’ what should I tell them?” God replied to Moses, “I AM WHO I AM. This is what you are to say to the Israelites: I AM has sent me to you (Exodus 3:13-14).”
God is unchangeable. “Because I, Yahweh, have not changed, you descendants of Jacob have not been destroyed (Malachi 3:6).”
God is holy. He is absolutely pure and sinless. He hates sin and loves goodness (Proverbs 15:9-26). He must separate Himself from sinners, and must punish sin (Isaiah 59:1-2).
God is just. Everything He does is right and fair. He fulfills all of His promises (Psalm 119:137).
God is love. Although God hates sin, He loves sinners (John 3:16-17).
Note: In speaking to God in prayer, we use words of respect to show reverence for God. It is improper to address Him in the same way we would speak to other persons. If we were to address the office of a president or a king, how would we address him? Remember that we are coming into the presence of the King of Kings every time we pray.