Bava Metzia 110b: If one appointed an agent to hire workers, neither he nor the agent transgresses “bal tolin” (the prohibition to delay a worker’s wages overnight). He does not transgress because he did not hire them, and the agent does not transgress because he is not withholding their wages.
בבא מציעא קי ע”ב: תנו רבנן: האומר לחבירו צא שכור לי פועלים ־ שניהן אין עוברין משום בל תלין, זה ־ לפי שלא שכרן, וזה לפי שאין פעולתו אצלו.
Reb Aharon Steinberg once posed a question: The Torah says, “See, I (Anochi) place before you today a blessing and a curse.” The Baal Haturim says that the word “Anochi” alludes to the first of the Ten Commandments. What does that commandment in particular have to do with this verse?
Also, the Torah promises a blessing if we listen to Hashem – but doesn’t the Gemara say that there is no reward for mitzvos in this world (Kiddushin 39b)?
Furthermore, Hashem Himself follows the Torah’s laws, so how can He postpone our reward, our “wages”, until Olam Haba?
The answer is that Hashem gave the Torah through an agent, Moshe Rabbeinu, and one who hires through an agent does not have to pay on the same day. But the first two of the Ten Commandments were given by Hashem directly to us. Therefore the reward for emunah and renouncing idolatry is paid in this world. Hence, “See that for the mitzvah of Anochi I place before you today, in this world, a blessing and a curse.”
Source: Beis Aharon