Romans 10:17 (NKJV)
What would it be like if you had to go to the doctor and they told you that you had a medical problem, but there was a pill you could take for that problem and you only had to take the pill once? If that was the case you would probably be very happy, but unfortunately there is no magic pill that you can take one time for anything. Normally, you have to take a pill or some kind of medicine repeatedly to get the desired results. The same is true with most things, just taking something once or doing something once will not get the same results as doing it repeatedly will.
The thing that is true in the natural world is also true in the spiritual world, frequent repetition is important. While you can do something over and over again just as a ritual, there is a spiritual truth behind the concept of doing something on a regular, repeated basis. For example, Romans 10:17 does not say that faith comes by having heard, it says faith come by hearing, and hearing. Romans 12:2 talks about our being transformed by the renewing of our mind, which indicates a continual process. Building faith and renewing our mind is something that is not just done at one time.
Sadly, many Christians don't spend the necessary amount of time learning, meditating on, and practicing God's Word to get the desired results. Too many Christians are looking for some magic spiritual pill, so to speak, that will solve all of their spiritual issues. Some believers go from meeting to meeting looking for someone to pray for them or give them a "special word" from God to do what will only come through repeatedly reading, studying, hearing, and practicing the Word. Don't be a "magic pill" Christian, make it a regular habit to spend time in God's Word building your faith, renewing your mind, and developing spiritually.