Why would you have to hold on?
Because there is an enemy arrayed against you that will try to take it away. That means you may have to exert some energy, or some vigor. Once you learn where the attack has gotten in, rise up with the word and drive it out.
Matthew 7:24-27
The Wise and Foolish Builders
24 “Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock. 25 The rain came down, the streams rose, and the winds blew and beat against that house; yet it did not fall, because it had its foundation on the rock. 26 But everyone who hears these words of mine and does not put them into practice is like a foolish man who built his house on sand. 27 The rain came down, the streams rose, and the winds blew and beat against that house, and it fell with a great crash.”
New International Version (NIV)
When the storm comes, rise up to meet it with the word. Sickness, poverty, fear. etc.