Standard of Worship of the Muslims During Battles

What was the standard of worship of the Muslims during the battles? Regarding this, Hazrat Musleh-e-Maud (ra) states:

“Everything in the world attains progress gradually. Even the greatest of feats are never accomplished in a single moment. Even in the time of the Holy Prophet (sa), not everyone observed the Tahajud prayer; rather, this habit was being instilled in them gradually and even though it is proven that sometimes the Holy Prophet (sa) would not offer the Tahajud prayer during battle; however, in the era of Hazrat Umar (ra), the Muslims would offer the Tahajud prayer even in the days of battle. It is possible that the Holy Prophet (sa) would also wake up for the Tahajud prayer during the days of battle, but it is proven that on certain occasions, he would not offer Tahajud [during the days of battle].

“However, in the era of Hazrat Umar (ra), the Muslims would offer the Tahajud prayer even in battle. Once, Heraclius decided to launch a sudden attack on the Muslims; however, after much discussion, it was ultimately decided that there was no point to launch a sudden attack because the Muslims did not sleep at night and instead would offer Tahajud. This is another hallmark of their progression which was not found in them in the early days and thus the Holy Prophet (sa) would have to greatly urge and exhort them to offer this but later even those who were weak had developed the habit to offer the Tahajjud prayer.”

(Khutbat-e-Mahmud, Vol. 13, p. 189)