2 Corinthians 10:1-2, 10-11

Now I, Paul, myself urge you by the meekness and gentleness of Christ—I who am meek when face to face with you, but bold toward you when absent! I ask that when I am present I need not be bold with the confidence with which I propose to be courageous against some, who regard us as if we walked according to the flesh.

For they say, “His letters are weighty and strong, but his personal presence is unimpressive and his speech contemptible.” Let such a person consider this, that what we are in word by letters when absent, such persons we are also in deed when present.