Yes, the Lord can be angry, but He wants to be generous and forgiving. To the Israelites He said,
“If anyone of the common people sins unintentionally by doing something against any of the commandments of the LORD in anything which ought not to be done, and is guilty, or if his sin which he has committed comes to his knowledge, then he shall bring as his offering…So the priest shall make atonement for him, and it shall be forgiven him” (Leviticus 4:27-31).
If the Lord wanted to punish, He would have done it the moment an Israelite sinned, but He desired a relationship with the children of Israel, and He used all that to show the world that He wants the same with the world, and that is why John 3:16 is so significant, God gave the world, His beloved Son.
All these laws in the Book of Leviticus lead to that grand passage.