Absolute perfection for the 144000
Absolute perfection suggests that all my actions are perfect and that everything which I do perfectly demonstrates God's character in every way. While we rejoice in the gift of life and righteousness we must understand that even though we partake of the very life of Christ, yet obedience to God depends upon how well we understand His will. God does not work independently of our will and our understanding. He does not reveal all truth to us immediately and it is His purpose to continue to lead us step by step through His word to an ever-increasing understanding of His will and His ways. One day there will be a people who have a complete understanding of God's will as far as man's life in this world is concerned and these people will represent Christ more perfectly than any other people have ever done. These will be the 144,000 and these will be perfect in an absolute sense as far as human perfection in this life is possible.
However, this does not contradict the reality that here and now, every single Christian may be and ought to be perfect. What does God require of me? All He requires is that I surrender to Him absolutely, without reservation. What else can I do? Everything else is the work of God. He must teach me His will, He must guide me into all truth step by step. Today as I surrender perfectly to Him, He will accomplish His will for today in me. Does God require or expect more of me than this? Absolutely not. Perfect surrender is all that God requires of us and so, when a person has fully surrendered to God, then that person is perfect in the eyes of God. Even when the 144,000 are absolutely perfect it will simply be that each day they surrender to God one hundred percent. Their surrender is no greater than the surrender of the true Christian today. The fact that God gives them more light is not an indication that they were more surrendered than others, but simply that God's purpose for the final generation involves a greater revelation of His will and character.
This is why the thief on the cross can be saved. His surrender was perfect and this will be the same for all who will be saved. God will have had full control of the person's will and therefore will have been able to give them His own life.