He said they would be very effective or specifically in his words they would “availeth much”.

Source:

James 5:16

I was a king but death comes for us all. When Isiah told me I would die I prayed to God for more life. God gave me another 15 years of life. Who am I?

I am King Hezekiah of Judah.

Source:

2 Kings 20:1-6

I was just a servant.  When I prayed to the God of my master he heard my prayer and answered it quickly. Who am I, also who is my master?

I am an unnamed servant of Abraham on a journey specifically to seek a wife for Issac.

Source:

Genesis 24:12-21

In his letter to the Colossians Paul mentioned a prayer warrior who prayed for a specific church.  Who was the prayer warrior also what church did he pray for?

His name is Epaphras and he especially  prayed for the church of Colossae.

Source:

Colossians 4:12

I was in fervent prayer to God, but the priest thought I had too much to drink. When the Priest realized his error he apologized. God granted my request and went above and beyond what I asked him, who am I?

Surely I am Hannah the mother of Samuel. God not only gave me Samuel but other children also.

Source:

1st Samuel 1:9-20

We don’t know much about this descendant of Judah. But God’s answer to his prayer inspired the writing of books. Who is this person?