Answered by Shaykh Shuaib Ally
Question: Can I pray the Maghrib prayer by the wudu of the Asr prayer?
Yes, it is permissible to pray multiple prayers with a single ablution.
This is the case unless you otherwise do something to break your wudu, such as using the washroom. Performing a prayer, obligatory or otherwise, isn’t one of the things that break one’s wudu.
It is nevertheless a Sunnah act to redo a wudu for another prayer you want to perform, even if you haven’t done anything to break it.
This is based on the Prophet’s statement, peace and blessings of God be upon him, “Whoever performs an ablution while in a state of purity, God decrees for him ten rewards” [Abu Dawud].
Source: Tuhfatul Muhtaj