Sometimes when I go to a party, they will serve coffee in those white plastic styrofoam cups. Now the only problem with those cups is that they all look alike. If you set yours down for a minute, it will be hard to find it again amid all the other identical cups that other guests are using.
So I do something clever.
I take my pen and write on my cup — “this is Greg’s cup.”
Problem solved. I can easily find my cup when I want it and no one else uses it because it is clearly marked with my name on it.
God does the same thing to you when you put your faith in Jesus Christ as Lord. He marks you as uniquely his by indwelling you with his Holy Spirit.
This is known as sanctification. God has set you apart for his specific use and purpose. He is announcing to you and everyone else that you belong to him.
But there is more. God expects us to keep ourselves clean and unpolluted from the world around us. Like a clean cup in the cupboard, we are ready and waiting for a guest to arrive, so God can pour out a blessing to them through us. If we are dirty and needing a good scrubbing, he surely will use some other cup and the loss will be ours.
Paul says it clearly in 2 Timothy 2:19-21 (NLT):
“But God’s truth stands firm like a foundation stone with this inscription: The Lord knows those who are his, and All who belong to the Lord must turn away from evil. In a wealthy home some utensils are made of gold and silver, and some are made of wood and clay. The expensive utensils are used for special occasions, and the cheap ones are for everyday use. If you keep yourself pure, you will be a special utensil for honorable use. Your life will be clean, and you will be ready for the Master to use you for every good work.”