That's your own disbelief, you're spiritualizing the text by reducing it into a "simile". Both are God's formula, neither is a "simile".
What disbelief? What spiritualizing? I'm just being rational based on a plain reading and understanding of the text.
I reduced nothing to a simile; they literally are similes,
by definition. More than that, you didn't address the fact that Psa. 90:4 gives two very different metaphors for one thousand years--"yesterday" and "a watch in the night." That alone proves my point, apart from those being similes. You
cannot say, based on that verse, that a thousand years is
equal to a day, but completely ignore that it is
also about four hours. That is simply choosing to make the verse say what you want.
Is a day equal to 1,000 years or 6,000? Is the earth 6,000 years old or 36,000 years old? You have to choose one or the other, according to your position.
And, that is the problem with ignoring the fact that it is a simile, a figure of speech, meant to teach us that time is essentially nothing with God. That is supported by what the rest of the surrounding context states. What one absolutely cannot do is use such figures of speech to determine what "day" we are in or how much time is left, especially since one must first assume the age of the earth.
The same goes for 2 Pet. 3:8. The context is clearly concerning the seeming delay of the return of Christ. So, Peter employs the same figure of speech to show that with God, time is different, and for him to wait a thousand years is but as a day to him. Peter wants his readers to be patient--it's all in God's timing. Why? As verse 9 states, "The Lord . . . is patient toward you, not wishing that any should perish, but that all should reach repentance" (ESV).