“On one occasion, Rabbi Levi Yitzchak conducted a search for someone to blow the shofar on Rosh Hashanah.
A number of men demonstrated their knowledge of the mystical meditations that are supposed to enhance shofar blowing, but he was not satisfied.
One day, a simple man came, and when Rabbi Levi Yitzchak asked him what he would have in mind when he blew the shofar, the man told him:
‘Rabbi, I have four daughters of marriageable age. When I blow the shofar, I will think, ‘Master of the world, I do Your will and blow the shofar, so please do my will and help me marry off my daughters.’
Rabbi Levi Yitzchak stood up and said, ‘You will blow the shofar in my synagogue!’
Of prime importance in a person’s intention is not his intellectual level, knowledge, or even spiritual preparedness but the degree of his intensity as he performs the mitzvah.
That makes all the difference.
In short, intent without a mitzvah is nothing, but a mitzvah without intent, even if it be meager, is still significant.
Performing a mitzvah for its own sake is the starting point. But when we combine intent with a mitzvah, we can arrive at great things.
The mitzvah is a sort of code, a specific, definite message, and the intention is the amplifier.”
From Understanding the Tanya, Chapter 37, p. 248, by Rabbi Adin Steinsaltz