In this verse David sees God as the One who resides in heaven. He asks if God from on high will stretch out his hands to save him and rescue him from the threatening waters. In Psalm 144:7b it becomes clear that the many waters does not refer to actual water, but it is imagery for enemies. The hand of foreigners
literally translates as children of strangers,
which does not necessarily mean enemies from abroad, for David also had enemies among the Israelites.
7 Stretch out your hand from on high; rescue me and deliver me from the many waters, from the hand of foreigners,