Towards the end of Parashat Pekudei, the Pasuk reads “VeLo Yachol Moshe Lavo El Ohel Moed Ki Shachan Alav HeAnan” “Moshe could not go into the Tent of Meeting because the cloud rested upon it” (40:35). Rav Moshe Feinstein in Darash Moshe asks, why was it impossible for Moshe to enter the Ohel Moed when the cloud rested upon it? When the cloud rested on Har Sinai, Moshe did not refrain from going up to accept the Torah.
Rav Moshe answers that the presence of the cloud over the Ohel Moed was a sign from Hashem that Moshe was not allowed to enter the tent. In this context, the phrase “Lo Yachol” means that Moshe was not allowed to enter the Tent of Meeting while the cloud was resting upon it. However, Rav Moshe did not merely offer this as an explanation to this Pasuk, rather he incorporated it into his own lifestyle. He was once at a convention to deliver a speech where he davened Maariv before going to the convention. Then, after the convention was over, there was a minyan for Maariv. However, Rav Moshe and the person driving him home were walking towards the exit. Suddenly Rav Moshe stopped in his tracks, and the person asked him why he stopped? He responded that I cannot move because the person in our path is in the middle of Shemoneh Esreih and the Halacha does not allow me to walk in front of him. This shows that Rav Moshe lived the Torah, and not only interpreted it.