1Peter 3:20 Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
God’s longsuffering is not so that goats can become sheep. That’ll never happen. He is long suffering towards the sheep, that they all might enter his fold. When the last one comes, His longsuffering is over.
God’s longsuffering waited in the days of Noah “while the ark was preparing”. Once it was prepared, and they entered, that was it. He already pronounced judgment on everyone else. His longsuffering was Noah’s salvation, otherwise he would have judged the world sooner.