We live for God by faith, not by knowledge although many act on certain points as if knowledge was essential and that they have it! Who has all knowledge, but God alone?
What is important to man? What is important to God?
"Behold, his soul which is lifted up is not upright in him: but the just shall live by his faith." Habakkuk 2:4
"For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith." Rom 1:17
"And though I have the gift of prophecy, and understand all mysteries, and all knowledge; and though I have all faith, so that I could remove mountains, and have not charity, I am nothing." I Cor 13:2
In order to have or keep faith with something you have to know to one degree or another the object of your faith. Indeed love is greatest and we live by faith but that is not contrary at all to definitely holding to things God revealed to us, such as the Trinity, that things were made out of nothing, the Incarnation of Christ, and so on. One can live by faith and hold to these things, as St. Paul himself did who you quoted here. Living by faith is not an excuse for a lazy and asinine anti-intellectualism when the Lord gave us an intellect and perfects it in us by the knowledge He reveals.