Why to pray?

Matthew 18:20 NAB For where two or three are gathered together in my name, there am I in the midst of them.
Luke 1:37 For nothing will be impossible to God.
Philippians 4:6-7 Have no anxiety at all, but in everything, by prayer and petition, with thanksgiving, make your requests known to God. Then the peace of God that surpasses all understanding will guard your hearts and minds in Christ Jesus.
James 5:14,15 Is anyone among you sick? He should summon the presbyters of the church, and they should pray over him and anoint (him) with oil in the name of the Lord, and the prayer of faith will save the sick person, and the Lord will raise him up. If he has committed any sins, he will be forgiven.