The choice to serve H'shem or disobey Him is up to us not up to Him. The actual ability to act out our intentions depends on external variables that H'shem controls and maneuvers at times leaving available and at times not.
pg 429
Nefesh Hachaim
Letters without punctuation and vowels have no meaning. It is for this reason they represent action, and the lowest level of the soul, the nefesh.
Gate Two, Chapter 16 pg 99/100