In the new testament, the example you where using is not what God was referring to. We have to remember that God is not changing, He is the Same today as yesterday Heb.13:8. In Rev.1:8 Jesus said He is the Alpha & Omega, who is and who was. John 1 tells us that Christ was in the beginning and that all things were made for Him. This same Christ was made flesh and walked with man because man lost site of the object or symbol of the ceremonial feasts that pointed to Christ as the true Lamb. God was showing that His law is immutable and we in the new testament era believe that Christ will no longer judge us as he did anciently, but we will be sorely disappointed. 1Peter 4:17,18 judgement will come to the house of God...If the righteous scarcely be saved, where shall the ungodly and the sinner appear. If there is a contradiction then it is our understanding, not that God has changed. People can not see that God is the originator of Life, and He showed how to live that life, when we walk apart from God, we would not be happy with God or His law. We say His judgement in the old testament as cruel and Him as a tyrant just as Satan has accused Him of being, but there is more love to end a life that will oppose the law of God(which is SIN) than to live in the misery of this world of sin. Not that we are to become judges of that and end lives, we live in the era of grace(which means judgement is not meet immediate).There is no peace as a sinner, and the end is death. God is Love, Jesus is Love, and David said it best, Psalm 1:1,2 Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.But his delight is in the law of the LORD; and in his law doth he meditate day and night. My friend the new testament was written for the people who already had an understanding of the OLD testament. God doesn't change, He would therefore be a liar and it would be unfair to those who lived then and no now and you and I would have no true hope for salvation. This may not have helped much but to get a full understanding, it takes Studding the word of God, not a brief reply, But I do pray that the Holy Spirit will lead you into all truth. There are some real good Bible stdies that I think would help, I will include the webesite.
Your fellow servant in Christ,