Rav Avigdor Miller on Repeating The Great Truths

Q:
What is the benefit of saying the Ani Ma’amins every day? I believe it. Why do I have to keep repeating it?
A:
The answer is that it makes a tremendous difference in a person’s emunah. Some people’s emunah is like a very thin layer of paint – you give a little scrape and the paint comes off. Some people’s emunah is thicker than that and you have to work all your life to achieve that. It’s not just a matter of repeating the foundations of truth because of some sort of a lack of emunah. It’s not just emunah that you are trying to work on – it’s da’as Hashem, Awareness of Hashem. All your life you have to become more and more aware of Hakodosh Boruch Hu. You remember when Moshe Rabeinu asked Hashem, הראיני נא את כבודיך – “Please show me your glory,” was it because he lacked emunah, chas veshalom?! No; he wanted to get closer and closer to Hashem.
And that’s why we say Ani Ma’amin; in order that each time we say it – if we say it properly – we’re making it more and more clear to ourselves. If you say it a thousand times you’re making a much deeper impression than saying it just once – even if you believed it the first time.
That’s why it is so important to repeat the same Kriyas Shema every day. And the same with all the tefillos. Every time you say it you are making it more and more deeply engrained into your mind. That’s why it’s so important to repeat the great truths over and over again. Instead of every day saying something new – No! – repeat the same things again and again, and spend your time impressing upon your neshama the great truths of the Torah.
When you repeat an idea over and over again it becomes part of your personality. The Chovos Halevavos says: המחשבה נמשכת אחר הדיבור – Your mind follows your words. Do you hear that important yesod? Your mind follows your words! Say the right words and your mind changes. The more you say the same words the more your mind becomes influenced by these words.
And therefore we say again and again “Shema Yisroel Hashem Elokeinu Hashem Echad.” Of course, you have to know what you are saying. Hashem means that He is the one who is havaya – He is the one who exists. He is the only one who exists. And He is mihaveh es ha’briyah – He is the one who causes the world to exist  And He is Elokeinu. He is ours. That means that He has chosen us to be His servants. And that’s why we must devote our lives to Him. And ואהבת את השם אלוקיך – you have to love Hashem.
Now, each time you say these words, you are making it more and more real to yourself. You become more and more convinced of the truth. It’s precious; it’s valuable. Don’t think it’s just a small thing – a small amount of to’eles. No, it’s a tremendous benefit each time. And therefore, each time you repeat the great truths, you are making yourself more and more of an ish shalem – a perfect person.