One of the reasons that the least popular meetings in the church are often either the evangelistic outreaches or the prayer meetings is that both of these engage head on with the powers of darkness. Once we are lost to him, satan is fine with us so long as we just stay within the safe boundaries of the church. He will tolerate us worshipping on Sunday mornings, and attending seminars and other Bible classes, but if we begin to pray or evangelise we are intruding on what he considers to be his territory.
This is why, when we venture out in prayer, we not only engage with God at a deeper level, but we also engage with the enemy. We begin to operate in the spiritual realm, and this attracts spiritual attention. Particularly fierce are the battles that are fought when we engage in concerted and persevering intercessory prayer. Satan knows that victory for him is impossible, but nevertheless he seeks to hold his captives, hoping that we, as God’s chosen representatives and enforcers, will give in and back off.