On what basis do you think God judges anybody? It's by His holiness. It's by His character. It's by His word. When Israel was under the Law, God's word told Israel to obey the Law, and that became the basis for Israel's judgment. It was in God's character to tell Israel what to do and expect them to obey.
God made Man in His image. He therefore expected Man to act according to His own character, His own holiness, His own love. What does that surprise you?
God's Law is holy.
That is the judge.
Show me where a single verse here is saying the law is past tense...
7 What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet.
8 But sin, taking occasion by the commandment, wrought in me all manner of concupiscence. For without the law sin was dead.
9 For I was alive without the law once: but when the commandment came, sin revived, and I died.
10 And the commandment, which was ordained to life, I found to be unto death.
11 For sin, taking occasion by the commandment, deceived me, and by it slew me.
12 Wherefore the law is holy, and the commandment holy, and just, and good.
13 Was then that which is good made death unto me? God forbid. But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful.
14 For we know that the law is spiritual: but I am carnal, sold under sin.
15 For that which I do I allow not: for what I would, that do I not; but what I hate, that do I.
16 If then I do that which I would not, I consent unto the law that it is good.
....notice that this is written decades after the cross.