The Word "Pray" is mentioned in New Testament( NKJV)_150 times. Prayer is talking to God through Jesus Our Saviour. Jesus said in,
"Matthew 7:7 NKJV
"Ask, and it will be given to you; seek, and you will find; knock, and it will be opened to you."_  so we can ask and God will surely give us/ answer our prayers.
"James 5:16
The prayer of a person living right with God is something powerful to be reckoned with."_ Righteousness.
Righteousness can be understood, from the following, instance.
Simply anyone who is dressed up as Traffic Police   can regulate, not because of the individual's ability, because of the authentication which this uniform brings. In the same manner, any of God's children who are clothed with the Righteousness of Jesus Christ, as it's  mentioned in,
"1 Corinthians 1:30 NKJV
But of Him you are in Christ Jesus, who became for us wisdom from God-and righteousness and sanctification and redemption-" People who are clothed with the Righteousness of Jesus Christ_their prayer avails much. Jesus Our sanctification, redemption and Righteousness. Hallelujah