These are possible answers that Christ used and that He may give us at the right time also if we have memorised them -
It is written
Have ye heard?
Go and learn what it means
Have ye read?
Let them alone
Take heed, beware
What thinkest thou?
Except ye become converted and become as little children
How think ye?
Friend
Did ye never read in the Scriptures?
Take heed that no man deceive you
Watch therefore
Watch and pray
Watch
Not my will but Thine be done
A house divided against itself cannot stand
Art thou a master in Israel and knoweth not these things?
I can of mine own self do nothing
It is written in the prophets
What is that to thee, follow thou Me
Tell me therefore which one of these will love him most?
Go and do thou likewise
Go and sin no more
But when they shall lead you, and deliver you up, take no thought beforehand what ye shall speak, neither do ye premeditate: but whatsoever shall be given you in that hour, that speak ye: for it is not ye that speak, but the Holy Ghost. Mark 13:11