Al-An'am: 164
{Say: Is it other than Allah that I should seek as a Lord?}
This is a response to their invitation for him to worship their gods. The interrogative particle (hamza) is for denial; meaning: Is it conceivable that I would seek a Lord other than Him?
{While He is the Lord of all things}
Everything besides Him is a subject (marbub). There is no one in existence who possesses Lordship other than Him, as He said: {Say: Is it other than Allah that you command me to worship?} (Az-Zumar: 64).
{And every soul earns not [sin] except against itself}
This is a response to their statement: {Follow our path, and we will bear your sins} (Al-Ankabut: 12).
{And it is He who has made you successors upon the earth and has raised some of you above others in degrees [of rank] by which He may test you in what He has given you. Indeed, your Lord is swift in penalty, but indeed, He is Forgiving, Merciful.}