Intention Matters

The Holy One, blessed be He, requires the heart, as it is written, But the Lord looketh on the heart.
-Sanhedrin 106b

R. Eliezer says: if a man makes his prayers a fixed task, it is not a [genuine] supplication.
-Berachoth 28b

It is the same whether a man offers much or little, so long as he directs his heart to heaven.
-Menachoth 110a

R. Judah says in the name of R. Eleazar b. Azariah: One who recites the Shema' must do so audibly, as it says, Hear, O Israel, the Lord our God is One, which implies. 'Let thine ear hear what thy mouth utters'. R. Meir says: [It says], which I command thee this day upon thy heart: according to the concentration of the mind, so is the value of the words.
-Megillah 20a

For Rab Judah said in Rab's name: A man should always occupy himself with Torah and good deeds, though it is not for their own sake, for out of [doing good] with an ulterior motive there comes [doing good] for its own sake.
-Pesachim 50b

Commentary: Judaism is often described as a religion of "deed, not creed" as if one's inner thoughts and motivation do not matter. However, we see from the above passages that the intention with which we do things is paramount. We should not only do the right actions, but also have the right feelings and motivations behind them. On the other hand, the last passage above suggests that the performance of good deeds for the wrong reasons will eventually lead to their performance for the right reasons.