I need also to explain briefly how we climb—or rather, are lifted—from the last level to the first. We are born on the lowest level of the physical world, and are lifted to the second level by means of factual knowledge. Then as we develop our discernment through this knowledge, we are lifted to the third level and become rational. The three ascending levels in the spiritual world are within this, resting on the three physical levels, and do not become visible until we leave our earthly bodies. When we do, the first spiritual level is opened for us, then the second, and finally the third. However, this last happens only for people who become angels of the third heaven. These are the ones who see God.
Angels of the second heaven and of the lowest heaven are people in whom the second and the lowest level can be opened. The opening of each spiritual level within us depends on our acceptance of divine love and wisdom from the Lord. People who accept some of this love and wisdom reach the first or lowest spiritual level; people who accept more reach the second or intermediate spiritual level; and people who accept a great deal reach the third or highest level. However, people who do not accept any divine love and wisdom stay on the physical levels, deriving from the spiritual levels only enough to allow them to think and therefore to talk and to intend and therefore to act—but not intelligently.
There is something else that we need to know about this lifting of the inner levels of our minds. Reaction is characteristic of everything created by God. Only life is action, while reaction is prompted by the action of life. This reaction seems to be proper to the created being because it becomes perceptible when that being is stirred; so when it happens in us, it seems to be our own. The reason is that even though we are only life-receivers, we have no sense that our life is anything but our own.
This is why we react against God as a result of our inherited evil. However, to the extent that we believe that all our life comes from God and that everything good about it comes from an act of God and everything bad about it from our own reaction, our reaction becomes a property of the action and we are then acting with God with apparent autonomy. The equilibrium of all things comes from action and immediate reaction, and everything must necessarily be in an equilibrium. I mention these things to prevent any belief that we ourselves climb up to God on our own power. It is done by the Lord.
from Divine Love and Wisdom, Section 67, 68