Prayer in the biblical version is defined as a means of communicating or talking with God. Lots of teachings where been made by prophets and disciples of Jesus Christ about effective prayers.

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JAMES TEACHING ON EFFECTIVE PRAYER

Some of the conditions of effective prayers are steadfastness, presserrvance and faith. St James said, (James 1:2,13-18)

• count it all joy, my brethren when you face various trials, for you know that the testing of your faith produces steadfastness and let steadfastness have it's have it's full effect, that you may be perfect and complete lacking nothing. If any of you lack wisdom let him ask for wisdom from God who givet to all men liberally and up braide is not and it shall be given to him but let him have faith without doubting for he who doubts is like a wave of sea that is driven and turned by the wind for that person must not suppose to doubt and also not to be double minded but if he ignores to be doubtless he will be unstable in the eyes of the Lord and will receive nothing from the Lord.
  In this he is just saying that Christians should pray believing that God will surely do what they ask him, no matter the temptation or suffering, Christians should and must preserve, they must not doubt because if the doubt they might likely not receive answers to their prayers.

REASONS FOR UNANASWERED PRAYERS

• lack of faith on the part of the person praying
• unforgiving spirit on the part of the person praying
• reputation of the same word
• lack of repentance from personal sin

Thanks for reading and God bless you