The ends don't justify the means.

John: We could achieve our goal much faster if we used this method, even though it's a bit shady.

Alice: I understand the temptation, but the ends don't justify the means. We need to stick to ethical practices.

John: But the consequences of missing the deadline are severe.

Alice: I agree, but compromising our principles is worse. We can't let the pressure lead us to believe the ends don't justify the means.