{ Musa said to his people: Appeal to Allah for help and be steadfast; indeed the earth belongs to Allah and He bequeaths it to whomever of His servants He wishes; the ultimate outcome belongs to the devout. They said: We have been harmed before you came to us and after you came to us. He said: Perhaps your Lord will destroy your enemy, and afterwards establish you in the land, so that He can see how you fare } Al-a'raf 128-129

Then He makes clear, by His word { So that He can see how you fare } , what follows in the way of exhorting them to hold firm in obedience to Allah.