Travailing prayer - A key to revival. 

Jesus said we must be born again to enter the kingdom of God.

"Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God." - John 3:3 KJV

Jesus is speaking of the spiritual birth of water baptism and Holy Ghost baptism. 

"Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God." - John 3:5 KJV 

Born of water and Spirit is baptized in water and Spirit. 

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost." - Acts 2:38 KJV 

When a soul is born into the kingdom of God, the spiritual mother – the church – baptizes with water in Jesus name. The Father – Jesus – baptizes with His Spirit. The church brings forth the soul in water baptism, while the Father breathes into him the breath of life, His Holy Spirit. 

It only makes sense that the mother - the church - must go through travail in order to give birth.  

"For as soon as Zion travailed, she brought forth her children." - Isaiah 66:8 

Travail is a word that describes a woman in labour giving birth to a baby. In the spiritual sense, we can see this travail as being very strong prayer.  

What kind of strong prayer? Physically consuming prayer…prayer with tears… praying in the Holy Ghost, speaking in other tongues as the Spirit gives the utterance.  

"My little children, of whom I travail in birth again until Christ be formed in you," - Galatians 4:19 KJV 

"But ye, beloved, building up yourselves on your most holy faith, praying in the Holy Ghost, keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life." - Jude 1:20-21 KJV 

"Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered. And he that searcheth the hearts knoweth what is the mind of the Spirit, because he maketh intercession for the saints according to the will of God." - Romans 8:26-27 KJV 

"Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;" - Ephesians 6:18 KJV 

Travailing prayer not only births souls but also brings rebirth of backsliders. 

Revival.