Glyph origins of the character 拜
「拜」was originally「」, comprised of「手・扌」and「」.


  「」(please read this in both meaning and sound as「禱」) depicts flowery adornments used in dances and religious prayer/rituals.
  
  商甲佚32合集1439西周金番生簋蓋集成4326秦簡日甲61背　篆說文解字　今楷　


The combination of「手」(hand) and「」(flowery adornments used in dances and religious prayer/rituals) indicated the meaning to conduct obeisance.

西周金沈子它簋蓋集成4330秦簡睡・秦153　

In the character「」, the bottom part of「」was sometimes corrupted into something that looked like「手」.

秦簡日甲166　

Similarly, the top part of「」, which is「卉」, was sometimes removed. This leads on to the modern form of「拜」.

東漢隸鄭固碑　今楷　



References:


季旭昇《說文新證》
小學堂
國學大師


郭沫若《甲骨文合集》
中國社會科學院考古研究所《殷周金文集成》