To your beliefs.
If the Jews had held on to their beliefs then we would never have had Christianity.
Peter changed his beliefs. Apollos had to. Paul took 15 years to work out what his belief was.
The point I think is that if we hold on to an abstract belief we crowd out God who by his Spirit is constantly blowing in new ways. Belief can be an idol that overshadows God himself.
The bible instead seems to ask us to remember. Remember what God has done. Remember what has been taught to you. Remember.
Holding on is too tiring. Let go and remember. And you might actually feel his arms from the past and the future holding your present.