Whilst turning your face in the direction of the Kaʿbah, simultaneously turn your heart towards the Lord of the Kaʿbah, Allah (ʿazza wa jall). Remove everything else other than Him from your heart.

When soldiers or opponents surrender, they will raise their hands, as if to say ‘You’ve got me. I’m all yours!’ Similarly, raising your hands in ṣalāh is a physical manifestation of your surrender to Allah (ʿazza wa jall). However, this differs from surrendering to another human. It is not a surrender of humiliation or weakness. Instead, it represents great honour and strength, for there is no greater honour in this world than being a true servant of Allah. Even before declaring himself the Messenger of Allah, the Prophet ﷺ described himself as the ‘servant of Allah’.

Ibn al-Qayyim (raḥimahullāh) described the raising of the hands as ‘the embellishment of ṣalāh’.

Go to Allah (ʿazza wa jall) and give yourself up to Him. As you raise your hands, throw the world behind you and get ready to converse with your Creator

1: Wudu: Inner and Outer Purification
The Qur'an & Its Virtues