He is unlimited by space. He can be and is everywhere at once.
As a mom of three and a MeeMa of two, I have often wished I could be everywhere at once. Just a few weeks ago, I babysat my two grandsons who are four and two. I put the two-year-old down for a nap and proceeded to attempt to get the four-year-old who never naps to be still so I could rest. While I was lying down telling him stories, the two-year-old got out of bed, found my deodorant, and used it to draw on my bedroom window. I found the evidence later that day.
What does this have to do with God being omnipresent? God has billions of people that He cares for daily. He knows their every need, and He is able to provide for them. We are limited to being in one place at a time, but He is not. He is as fully present with one person as He is with another. Taking care of one child does not limit His ability to take care of another.
His omnipresence also means we cannot hide from Him. My two-year-old grandson took the opportunity of my absence to perform his artistic work on my window. Likewise, we sometimes think that God is too busy with others to see or care what we are doing. Which is not true, since He is capable of being fully presence at all places at all times. We cannot hide from God.
Where can I go from Your Spirit? Or where can I flee from Your presence? If I ascend into heaven, You are there; If I make my bed in hell, behold, You are there. If I take the wings of the morning, and dwell in the uttermost parts of the sea, even there Your hand shall lead me, And Your right hand shall hold me. If I say, “Surely the darkness shall fall on me,” even the night shall be light about me; Indeed, the darkness shall not hide from You, but the night shines as the day; the darkness and the light are both alike to You. Psalm 139:7-12
God’s omnipresence should cause us to glory not despair. If God could be hidden from, then we could be lost and unattended. His ability to be everywhere at once is to our benefit. To this characteristic of Omnipresence, God has also added the promise I will never leave you nor forsake you (Hebrews 13:5). When we learn to fully trust in His character and His word, we will be able to live at peace knowing that God is always watching over us.