Sunan ad-Darimi 739

The noble Companion Abu Sa‘īd al-Khudri (may Allah be pleased with him) relates: “Two men set out on a journey, and prayer became due”, meaning: its time came. “While they had no water. They performed dry ablution, using clean earth”, meaning: they turned to the earth and used it in the way specified for dry ablution. “Later on, they found water while still within the time of the prayer.

One of them repeated his prayer with ablution”, meaning: either because he thought his first prayer was rendered invalid or he simply wanted to err on the side of caution. “And the other did not”, meaning: based on the thought that his first prayer remained valid. They then went to the Messenger of Allah (may Allah’s peace and blessings be upon him) and mentioned what happened to him. To the man who did not repeat the prayer,

the Prophet (may Allah's peace and blessings be upon him) said: “You have followed the Sunnah”, meaning: your act accorded with the established teachings of the Sunnah. “He then said to the one who performed ablution and repeated his prayer: ‘For you there is a double reward”, meaning: you will have a double reward for your prayers, for both are valid and each entails a reward, and indeed Allah does not cause the good deeds of His slaves to go to waste.

This indicates that it is better to do what is safer and more cautious. In another Hadīth, the Prophet (may Allah's peace and blessings be upon him) said: “Leave what is doubtful for what is not doubtful.”