Psalm 70

Let all those who seek You rejoice and be glad in You;
And let those who love Your salvation say continually,
“Let God be magnified!”  v.4

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This psalm is almost copied word-for-word from psalm 40 (from verse 13 to the end); perhaps the reason in the title "To Bring Remembrance".  How often it is that we pray the same prayer over and over again, or use the same wording or verbage, so to David prays a similar prayer.  We are not sure if it's the same occasion or a different one from when he wrote psalm 40.  In this verse four when he writes, "Let God be magnified!" uses Elohim for God, whereas in psalm 40 Jehovah is used.  Learning why the Israelites used different names of God at different times helps us understand more of God's character and relationship status between God and man.  
Magnify means to increase the apparent size, to cause to make something greater or more important.  God can't obtain more glory than the infinite worth he had from all eternity. So if we can't make God seem bigger  than he already is, what does it mean for God to be magnified?

To magnify God 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". But can mean to make God more important in our life.  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.  How can you let God be magnified in your life by putting him first as your focus and priority?