Here is the reason we should know, speak and do the Word of God.
Read: Isaiah 55: 10-11
10 “The rain and snow come down from the heavens
and stay on the ground to water the earth.
They cause the grain to grow,
producing seed for the farmer
and bread for the hungry.
11 It is the same with my word.
I send it out, and it always produces fruit.
It will accomplish all I want it to,
and it will prosper everywhere I send it.