Just because “Oh my God!” is abused in our culture—a case of taking great God’s name lightly and in vain—doesn’t mean we should refrain from the vocative “O my God!”
Note in the Bible how often it is used in conjunction with imploring God to listen, to see, to remember, to arise, and to save.
2 Chronicles 6:40
Now, O my God, let your eyes be open and your ears attentive to the prayer of this place.
“O my God, I am ashamed and blush to lift my face to you, my God, for our iniquities have risen higher than our heads, and our guilt has mounted up to the heavens.
Remember for my good, O my God, all that I have done for this people.
Remember Tobiah and Sanballat, O my God, according to these things that they did, and also the prophetess Noadiah and the rest of the prophets who wanted to make me afraid.
Remember me, O my God, concerning this, and do not wipe out my good deeds that I have done for the house of my God and for his service.
Then I commanded the Levites that they should purify themselves and come and guard the gates, to keep the Sabbath day holy. Remember this also in my favor, O my God, and spare me according to the greatness of your steadfast love.
Remember them, O my God, because they have desecrated the priesthood and the covenant of the priesthood and the Levites.
I provided for the wood offering at appointed times, and for the firstfruits. Remember me, O my God, for good.
Arise, O Lord! Save me, O my God! For you strike all my enemies on the cheek; you break the teeth of the wicked.
O my God, I cry by day, but you do not answer, and by night, but I find no rest.
O my God, in you I trust; let me not be put to shame; let not my enemies exult over me.
Do not forsake me, O Lord! O my God, be not far from me!
I delight to do your will, O my God; your law is within my heart.”
As for me, I am poor and needy, but the Lord takes thought for me. You are my help and my deliverer; do not delay, O my God!
Deliver me from my enemies, O my God; protect me from those who rise up against me.
Rescue me, O my God, from the hand of the wicked, from the grasp of the unjust and cruel man.
O God, be not far from me; O my God, make haste to help me!
I will also praise you with the harp for your faithfulness, O my God; I will sing praises to you with the lyre, O Holy One of Israel.
O my God, make them like whirling dust, like chaff before the wind.
“O my God,” I say, “take me not away in the midst of my days—you whose years endure throughout all generations!”
O my God, incline your ear and hear. Open your eyes and see our desolations, and the city that is called by your name. For we do not present our pleas before you because of our righteousness, but because of your great mercy.
O Lord, hear; O Lord, forgive. O Lord, pay attention and act. Delay not, for your own sake, O my God, because your city and your people are called by your name.