Sometimes we think of faith as our own choice: "I choose to believe". Yet the fact is that unless God reveals Himself to us, none of us can know much about Him, much less know Him personally. Faith is how we thank God for revealing Himself throughout salvation history, most perfectly in Christ, and today by the work of the Holy Spirit in the Church.
Though God plants the "seed" of faith, like any other virtue, we develop faith through practice, not just by thinking and studying about God, but by taking time each day to have personal encounters with Him. Saint Paul tells us that, "At present we see indistinctly, as in a mirror, but then face to face" (1 Corinthians 13:12), meaning that in this life, the virtue of faith only allows us glimpses of God, and that we must await life after death to see God Himself, as He is.
We've all heard the expression "Doubting Thomas" used to describe someone who, like Saint Thomas the Apostle, needs to see in order to believe. By making a conscious effort to live in God's presence here and now, we can be assured that Christ will one day say to us, "Blessed are those who have not seen and have believed" (John 20:29).