I have remarked earlier that these attributes are difficult to grasp because they describe truths about God that have no analog in human experience. We are limited as to place, power and personal knowledge. God is not. Thus we say that God is omniscient (all-knowing), omnipresent (present everywhere), and omnipotent (all-powerful).
Theologians sometimes speak of God’s attributes in two categories—communicable and incommunicable. That sounds strange until you remember that we commonly speak of communicable diseases—diseases that can be spread from one person to another, such as chicken pox. Incommunicable diseases are those that cannot be spread from one person to another, such as rheumatoid arthritis or most forms of cancer.
When this distinction is applied to God, communicable attributes refer to those aspects of God’s character that we may share in some way—such as mercy, grace, anger, justice, and holiness. Incommunicable attributes are those that are unique to God and unshared in any way by his creatures. The three “omni” attributes fall into this category.
The word means “all-powerful” and refers to the fact that God’s power is infinite and unlimited. He can do with power anything that power can do. Said another way, God has the power to do all he wills to do. He has both the resources and the ability to work his will in every circumstance in the universe.
If you prefer a simpler definition, just think of these three words—”God is able.” That’s what omnipotence means. He is able to do everything he needs to do or wants to do.