Moses had to raise his staff, and even Jesus either SAID or DID something at EVERY healing/resurrection. We have not one single account of Him just "thinking" people to health or life. Moreover, in the one case where He "could perform no mighty works," the people had no faith. So clearly faith is absolutely necessary for a "powerful Christian." And your earlier mis-applied scripture on being weak in one's self in NO way contradicts my point. Paul did not say that he didn't have to actually DO something. He did. He preached, he debated, he laid on hands, and so on.
Consider this: the lame man at the Gate Beautiful was lame all his life. Jesus walked through that gate dozens of times in His ministry. Yet the man never got healed. Why? If Jesus had the power devoid of faith, merely His presence would have caused people to get healed. But it didn't.
The lepers were not cleansed until they ASKED for healing; even the woman with the issue of blood had to TOUCH the hem of His garment. Yet if you are right, He would have just walked around and people would be coming out of graves. But they didn't. Again, (and you didn't address this) Jesus and all the apostles constantly instruct us to DO things to obtain power---Peter said you had to ADD to your patience lovingkindness, and so on. It does NOT happen automatically. Hence, plenty of powerless Christians. Want me to introduce some to you?
I don't know any.
Rev 3 15 I know thy works, that thou art neither cold nor hot: I would thou wert cold or hot.
16 So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.