We must always remember that by doing what Hashem expects of us, we will never lose out. The condition is that we must put aside all personal calculations about whether it can work, and instead focus exclusively on the shelichus that we have before us from Hashem.
This is what the Yidden in prewar America did every Friday when giving notice that they would not be coming to work on Shabbos—knowing that they would be fired. There were no cheshbonos: Chillul Shabbos was just not an option! This is what Hashem wants; and He will give me the ability to persevere. Practically, it makes no sense. But we do it, because this is our mission.
The same applies to every aspect of avodas Hashem. A chessed that seems difficult to carry out, learning and davening as mentioned above, and so many other examples. All we need to do is our small part as shlichim of HaKadosh Baruch Hu, and Hashem will surely shower us with the ability to accomplish His mission.
