Allāh’s sustaining of His creation is of two types:
General: His creating them, providing for them, and guiding them to everything that they need for their survival in this world.
Exclusive: His sustaining His friends, by blessing them with Īmān, giving them the ability to accept it, and work fully to its demands. This, together with protecting them from those threats which endanger their Īmān. In other words, granting them the ability to do all that is good, while protecting them from all evil. Perhaps this is why the vast majority of the du‘ās of the Prophets عليهم السلام started off with Rabb/Rabbana, because all their aspirations fell under this exclusive type of ربوبية (Sustainment).
(Paraphrased from the tafsīr of Shaykh ‘Abdur Raḥmān ibn Nāṣir As-Sa‘dī رحمه الله)