I will do my homework, but my question was this:
Forget PT for now, where in the Bible does it say God restrains Himself?
PT? God pronounces judgment. When the people repent, it says God relents. God also said He would destroy men, but then relented or restrained Himself because of Noah. He also could wipe us out again, but He said he would restrain Himself and not send a Flood again (rainbow promise). Every time God extends mercy instead of judgment, He restrains Himself.
When God changed His mind about Hezekiah, He restrained an intention to do something different.
God is personal, so He can do what He wants if and when He wants. He can even change His mind (Bible says ?37x in response to changing contingencies, consistent with His character and purposes).
Jesus could have called legions of angels, but did not. This is God with a face restraining independent exercise of His power to do the Father's will. God is more free than we are.
The fact that God could have killed Hitler or stopped any form of evil by any individual or group shows that He is patient, not impulsive. This is a form of restraint. If He always exercised justice vs mercy immediately, there would be no restraint. He talks about His anger burning, but the prayers of a few restraining Him (Lot e.g.). He looks for intercessors to stand in the gap. If He does not find any, He goes ahead with something that could have been different. This is not a misleading representation of God and His ways, but the way He actually is. Prayer is not just for our sake, but can actually influence God, by His choice, for various reasons. Calvinism (you have some vestiges of it) has a different paradigm that must distort Scripture vs accept it.