How should a person's intention be when performing a good deed: should it be for the sake of Allah and His Prophet (peace be upon him), or for the sake of Allah and out of love for the Messenger (peace be upon him) and his Sunnah, or for the sake of Allah Almighty only?

Worship must be exclusively for Allah Almighty alone, as Allah commanded in His Book and the Sunnah of His Prophet. It is not permissible to associate anyone with Him in worship; rather, He must be singled out for it. The right of the Prophet, peace and blessings be upon him, and love for him, are fulfilled by following him and magnifying his Sunnah, not by directing worship to him.

For worship to be accepted by Allah, two conditions must be met: sincerity to Allah Almighty, and following the Prophet, peace and blessings be upon him, as Allah Almighty says: "So whoever would hope for the meeting with his Lord - let him do righteous work and not associate anyone with the worship of his Lord."