In speaking of God, speaks of him regarding temporal succession;

In Exodus, when God is conversing with Moses, this takes time.

Statements like God is Lord [over us] seem to suggest real relations between God and creatures. 

From the question of speaking of God in terms of temporal succession, Aquinas gets to a discussion of the relations between God and creatures. 

X can be related to Y in three ways.  In the first way, we conceive the relation between X and Y in our thinking, a relation that exists only in thought, but no reality.  If we say something is identical with itself (X = X), we are mentioning the same thing twice, the relation of this thing with itself, treating it as having a relation to itself, but that self-relatedness belongs to and only to our thinking; in reality it is itself, it is the way ti is and no other thing. 

Another example: two concepts are related as genus and species, that’s the way I think about those concepts.

This first example of X – Y relation is known as ‘relations of reason’: we talk about them only because of the way we think about them.  This type of relationship is opposed to real relations, that when there is an X – Y relationship it is true because of something real about X and about Y.  For example, if we say John is the father of Henry and Henry is John’s son, in reality Henry is John’s son (assuming the statement is true) and vice versa; if we say a quart is twice the size of a pint, it really is the case that the pint is half the size of a quart, and vice versa.  We don’t just think of the pint or of Henry in certain kinds of ways. 

A third possibility is that right now, the way I’m facing, the desk is to my right; if I turn around, then now in the way I’m facing, the desk is to my left.  The only thing that changed was my direction, but nothing changed about the desk; the desk only changed in relation to something about me.  The statement is true in each instance because of some real feature belonging to me, not the desk.  In this case there is a real relation of X to Y, but not a real relation between Y and X, because there is no determination belonging to the desk that differs in each case.  The former statements are true on account of some real feature belonging to only one of the things.