Complex sentence: Acting upon a command of God given to him in his dream, when Abdul Muttalib rediscovered the well of Zamzam, he found in it many valuable things that were buried in it very remote past by the Ismailites when they feared that their enemies would usurp them.
Split into simpler sentences: Acting upon a command of God given in a dream, Abdul Muttalib rediscovered the well of Zamzam. He found in it many valuable things that had been buried in a remote past by the Ismailites when they feared that their enemies would usurp them.