Luke 21:15 for I will give you a mouth and wisdom which all your adversaries will not be able to contradict or resist.
How many times have you tried to rehearse what to say for an important occasion only to get it all totally wrong or to be confused because somebody else did something wrong in your eyes?
As much as we think we can prepare for all occasions there will always be something we miss out on because each person thinks differently.
God wants us to learn His word and to be prepared for as much as we can be, but when the time comes we have to rely on Him for the final words.
Study and be prepared! But also be prepared to ask for help!