The God of the OT and NT are the same God; there is no real distinction. The only difference is that in the OT, Jesus was not incarnate yet, but while incarnate, He specifically tried to live a life for humans to imulate, which meant excluding some behaviours that God would do. For instance, Jesus said “I did not come to judge, but to forgive,” and yet He says God is the judge, and only He has the authority to judge, exact vengeance/justice, etc. But there is no real contradiction. Christ didn’t say, “I can’t and never will judge.” He merely said, I didn’t
come to judge. The Bible also says that Christ can and will judge, especially in the Last Day. But if He judged people while alive, and then told people to imulate Him, people would judge others, and so He didn’t do that. But God in the OT, since he was not yet incarnate, fully performed every action of God, which included exacting judgement, justice and punishment on people, while still being supremely merciful and loving to everyone. People greatly exaggerate God’s killing in the OT, and also ignore why God did kill when He did in the OT, which was always for a good, just reason.
But, to answer the specific question of the topic creator. While the OT does use some human-like descriptives for God that a spirit would not have, such as mentioning God’s “back” or “face”, they mean something real, and when it says God “spoke” to people, He does that in many different ways; one of which is audibly. Through the burning bush, God audibly spoke to Moses, and He spoke to a later prophet (I forget who) through a soft, gentle wind atop a mountain, but most of the time, God spoke through an angel. In the NT, that is unnecessary. We have Christ, the Face of God, who is physically present at every single Eucharist, and the Holy Spirit, our Divine Advocate in a personal, constant inner presence of God that makes every baptized heart the Kingdom of God in His dwelling.
