In our worship to God many times we utter phrases like "God I magnify you" or "God be magnified". I used to wonder, is God really magnified by saying those words? How can we really magnify God or have him magnified?
Clearly, those phrases can't mean that we have the ability to alter God in any way. I don't think that the definition of "magnify God" in these phrases means to actually make God "bigger" or "greater". I understand them to mean "Make God more prominent in my life, our culture, etc."
Magnification doesn't make objects bigger, it alters our perception of an object, making it appear bigger to us.
Similarly, magnifying God doesn't make Him bigger, it means He becomes more prominent to us.
The phrase "God, I magnify you" simply means "I am making you greater (more important) in my life, and putting you first, because you are my focus and priority."
They're probably just taking this verse literally:
Psalm 70:4 KJV Let all those that seek thee rejoice and be glad in thee: and let such as love thy salvation say continually, "Let God be magnified".
Though more modern translations usually replace "Let God be magnified" with "God is great!". It's simply a statement of praise meant to worship the Lord.
So then your question, are we really magnifying God by saying these things? If by magnifying you mean worshiping then, if our hearts are sincere, yes we are! But if you mean are we literally magnifying him, making him bigger, stronger, etc... then most certainly not. God is the same yesterday, today, and forever.