Because God's opponent is the Ruler of this world till the time when Jesus Christ comes back (Luke 4:5-7) prayers are the most effective weapon which Christians have to fight their real enemies (Ephesians 6:12).
We know, prayers are the reason why poeple like you are so successfully by giving Christians a home here on Steemit, so we should pray furthermore to the Lord, who's so much more powerfull as all creatures who tried to stop the preaching of the Gospel.