God’s infinity in relation to space is called immensity because “immense” is associated with “large” and “huge,” and also with extension and spaciousness within extension. God’s infinity in relation to time, however, is called eternity because the phrase “to eternity” means “in an endless succession of stages measurable in units of time.” To clarify: we describe the earth itself and its surface in spatial terms and the earth’s rotation and orbit in temporal terms. The earth’s motions anchor our measurements of time, and the earth itself anchors our measurements of space. In consequence of our senses, space and time are also present in a similar way in the perception of our minds as we reflect. In God, however, there is no space and time, as I have shown just above, yet space and time originate from God. Therefore “immensity” means his infinity in relation to space, and “eternity” means his infinity in relation to time.
Angels in heaven see God’s immensity as the divineness of his underlying reality and God’s eternity as the divineness of his capacity to become manifest. They also see God’s immensity as the divineness of his love and God’s eternity as the divineness of his wisdom. The reason is that angels remove space and time from divinity; this gives rise to the concepts just mentioned. Since we on earth cannot help basing our thinking on ideas that are spatial and temporal, we cannot conceive of the immensity of God before there was space or the eternity of God before there was time. In fact, if we try to conceive of them, our mind more or less loses consciousness, like a shipwrecked person who has fallen in the ocean or like someone being swallowed in an earthquake. Indeed, if we rashly persevere in that pursuit, we can easily go insane and end up denying the existence of God.
Once I myself was in a state like that. I thought and thought about what God did from eternity, what he did before the world was constructed. I wondered whether he debated the act of creation and worked out a sequence he would follow. I pondered whether mental debate was possible in a pure vacuum, and other useless questions. To prevent these considerations from driving me insane, the Lord lifted me into the atmosphere and light of inner angels. As factors related to space and time in my former thinking were somewhat removed there, I became able to understand that God’s eternity is not an eternity of time. Since there was no time before the world came about, I realized that it was completely pointless to ponder such questions about God. Furthermore, since the Divine “from eternity,” that is, the Divine independent of time, did not involve days, years, and centuries—they were all an instant for God—I concluded that God did not create the world in a preexisting context of time; time was first introduced by God as part of creation.
In addition, I would like to relate something worth mentioning. At one extreme end of the spiritual world, two statues of monstrous human forms appear with wide open mouths and gaping jaws. People whose thinking about God from eternity is pointless and insane seem to themselves to be swallowed up by these statues. The statues are really the delusions people hurl themselves into when they think discordant and unseemly thoughts about God before he created the world.
from True Christianity, Volume, Section 31