What did Jesus do? How did he get people's attention? Did he scream from the rooftops or did he first meet a physical need?
Jesus did not come to meet people's physical needs.
He came do die on a cross for us.
He only did healings and miracles to testify he was the messiah.
He did not heal everyone.
Sometimes he just walked away while a big crowd was looking for him.
He never needed to scream from the rooftops, just as we don't need to scream today.
Why?
Because Proverbs says that God's wisdom, and his spirit, are continually crying out to people from every corner.
Jesus attracted crowds because he "spoke with authority", and not as the scribes and pharisees.
He spoke in ways no one spoke, and he spoke with wisdom which no one else had.
His words were penetrating and mesmerizing, and instantly recognizable as truth... just as the written scripture is today.
To answer the OP:
God does not need defending.
But that does not mean we should never speak.
There are times to answer questions, and times to contend for the truth against falsehood.
If someone says God doesn't exist,
there are many scientific, historical/prophetical, and philosophical proofs.
Yet the bible says that each man, in his own heart, knows there is a God.
So what do we do?
Do we speak or not speak?
We should be ABLE to answer questions... and then do as God leads us in each situation.