"Will you just pray with us now?"
"We just ask that you hear our prayer..."
Two different usages of the same word imply two very different meanings.
In the first instance, "just" implies a similarity to "only" or "merely," as in "will you merely do this one thing."
In this example we can assume that the one thing (in this case, a prayer) is either of such great importance that it is the only thing that will be asked of us, or that it is of little significance due to the minimal participation it requires.
In the second instance, "just" implies a similarity to "only" also, but in the sense that it means "simply" or "solely," as in "we simply ask this of you."
In this context it seems the significance is of a more meaningful type, such that the sole asking of this one thing will, if granted, be sufficient to the asker.
I get my first example from a very successful speaker (can't call him a pastor without diminishing the role of a real man of the cloth) who frequently asks his audience (can't call them a congregation...) to participate in "asking Jesus into their hearts." In effect this is a typical "alter call," but with the notable insertion of the term "just," with all its previous indications intact.
Would it not serve his purpose to implore the audience to pray with him without using that word? I fear he does not realize that he reduces the act of addressing God in prayer exponentially by suggesting that they are "just" talking to God.
This is the holy Lord of the universe, the Creator, the Savior, the Comforter, our Priest. And that thing they are asking of Him- a convoluted version of saving grace- is worthy of much, much more than a simple nod of the head and a pre-scribed prayer.
The act of loving sacrifice of His own Son for us is, in fact, the only hope we have in the world. It is not just anything. It is everything.
I have pondered on the use of "just" in our daily prayers, which is where I derive my second example. Are we to diminish ourselves in our asking things of Him? Are we to just thank Him?
The first answer is yes, the second is no.
In our asking of Him, particularly when it is an asking of Him to hear our prayers, we ought to be nothing but humble. We ought to simply, merely be asking of Him that He bend His ear to us. Likewise in our asking of continued sustenance we ought to do the same, with a keen observation of our position (low, bowed) in regards to Him (Most High).
However, when we thank Him, there can be no amount of praise that surpasses that which He deserves. We are not just thanking Him, unless you consider giving your whole life and livelihood up to Him as a small gesture.