It was narrated from Ibn ʼUmar that ‘Umar (رضي الله عنه) - and I think he attributed it to the Prophet (ﷺ) said:
`Allah, may He be blessed and exalted - says: `Whoever humbles himself before Me like that” – and he turned his palm down towards the ground like that, very close to the ground - ` I will raise him in status like this` - and he turned his palm up towards the heaven and raised his hand like that.