At the very end of Tractate Menachot, the Mishna makes a very acute observation. It indicates that in the Portion of VaYikra we read about the various sacrifices. Some sacrifices call for a big ox. Others call for pigeons. After each sacrifice, large or small, the Torah says: אִשֶּׁ֖ה לַיקֹוָֽק, “a fire offering to Hashem”. (Lev. 1,16; 2,17, and others)
The Mishna explains: לומר לך: אחד המרבה ואחד הממעיט ובלבד שיכוין את לבו לשמים, “To teach you that it is the same whether a man offers much or little, so long as he directs his heart to heaven.”
One would assume that the Mishna is referring to the poor donor who feels somewhat uneasy about his meager sacrifice and he is heartened not to feel discouraged as long as his heart is directed to heaven.
A great Chassidic Rabbi explained it differently. On the contrary he said. It is talking to the wealthy person who offers a great sacrifice and feels that he has done a great deed even if his intentions were not “for heaven” but perhaps for the honor he gets. The Mishna is telling him, his intentions should be directed “for heaven”.