Q: What has the priority, the head or heart?
A: ...Now by heart I don't mean feelings or sentiments or emotions. Those are like waves. They're wonderful. They're fun to surf on. You can't build on them. A biblical focus always aims at the heart, the pre-functional root out of which all the functions grow, out of which all the branches come. The danger of doing that is that you forget the head or that you subjectivize it, or that you become skeptical of it, or that you oppose the head to the heart, or that you reduce the heart to sentiment. But those are dangers that you don't need to succumb to.
The primacy of agape love, rather than the primacy of reason, certainly seems to be a scriptural emphasis. [Thomas] Aquinas, as usual, is wonderfully balanced here. In asking the question whether knowing or loving is the highest thing, he gives a very nuanced answer. He says, "With regard to the universe, knowing is higher than loving. With regard to God, loving is higher than knowing, because when you love something you become more like it. When you know something, it becomes more like you."
When I know a stone, I raise it up to my level because I give it a second life. I make it a thought. When I know God, I drag him down to my level. I reduce him to what I can know of him, and therefore when it comes to relating to God, loving God makes you more godlike than knowing God. And therefore its higher.
Source: Peter Kreeft