Lord, Lord, did we not in Your name perform many miracles? Who were these?

[tonychanyt]

Matthew 7:

22 Many will say to Me on that day, ‘Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?’ 23 And then I will declare to them, ‘I never knew you; leave Me, you who practice lawlessness.’

They knew about Jesus and the verbal methods but Jesus never G1097-knew them intimately. The knowledge was one-sided. It was not a bi-directional relationship.

What is the power source behind the miracles, signs, and wonders?

It could come from Satan, 2 Corinthians 11:

14 no wonder, for Satan himself masquerades as an angel of light.

However, ultimately, all powers came from God, Psalm 62:

11 One thing God has spoken, two things I have heard: “Power belongs to you, God,

Is the passage talking about genuine signs and wonders of God or counterfeit miracles of Satan?

It could be both.

Can God actively use someone in signs and wonders and still prohibit them from entering His kingdom?

Yes, the person can fall away from God later in his life, 2 Peter 2:

20 If they have escaped the corruption of the world by knowing [G1922] our Lord and Savior Jesus Christ and are again entangled in it and are overcome, they are worse off at the end than they were at the beginning. 21 It would have been better for them not to have known [G1921] the way of righteousness, than to have known [G1921] it and then to turn their backs on the sacred command that was passed on to them.”

They had a G1922-knowledge of the Lord and they G1921-knew the way of righteousness, but Jesus did not G1097-know them intimately.

 

[Diamond7]

What is the power source behind the miracles, signs, and wonders?

It is not always easy to come up with scientific evidence for miracles. For one thing you have to go beyond the placebo effect.