Q: Why do we praise God in our Tefillot? Does God need/ want our praise?

A: Let us start with a different question: Why the particular praises that we do say?
If we examine the praise that introduces the Shemoneh Esreh, we will find that the
particular praises are very carefully chosen, and shed a lot of light on why we
praise God in the first place.
Sometimes what it doesn’t say is at least as important as what it does. There are
so many things we could say about God’s greatness that we don’t. The second
berachah of Shemoneh Esreh focuses on God’s power. We might have expected it
to talk about thunder and lightning, earthquakes and floods. It doesn’t. Rather, we
say that God is mighty in that He feeds the hungry, supports those that fall, heals
the ill and frees those that are in bondage and resurrects the dead.
On one level, this teaches us what true might is- the power to create, not destroy
[as noted by Rav Yosef Albo in Sefer HaIkkarim (IV:35)]. However, there is a
further aspect, which is more fundamental to the meaning of praise in our prayers.
We begin our Tefillah by asking God to help us open our mouths in prayer. It is not
a simple matter for us to feel the necessary confidence to approach the master of
the Universe and ask for what we desire. Many people, in fact, are so convinced
that the Creator couldn’t possibly be troubled by our concerns, that they refrain
from turning to him at all.
In the first berachah of praise we focus on God’s compassion. We note that God’s
desire to benefit others was the reason for the creation in the first place. We talk of
God’s love for mankind in general, and for the Jewish People in particular. The
second berachah follows with specific expressions of this love!
The praises that we introduce our prayers with serve a very clear and crucial
purpose. Before approaching God with our requests, we first remind ourselves that
there is every reason to believe that God would answer them. We remind
ourselves of God’s relationship with us and of His compassion. Only then are we
prepared to begin the Bakashah section, in which we ask God for what we need
and want.