From page 90 of Think, in a chapter entitled Loving God:
The main reason that thinking and loving are connected is that we cannot love God without knowing God; and the way we know God is by the Spirit-enabled use of our minds. So to "love God with all your mind" means engaging all your powers of thought to know God as fully as possible in order to treasure Him for all He is worth.
God is not honored by groundless love. In fact, there is no such thing. If we do not know anything about God, there is nothing in our mind to awaken love. If love does not come from knowing God, there is no point calling it love for God. There may be some vague attraction in our heart or some unfocused gratitude in our soul, but if they do not arise from knowing God, they are not love for God.