Matthew 10:19-20

But when they deliver you up, be not anxious how or what you shall speak; for that which you shall speak shall be given you in that hour:

Luke 12:11-12

When they bring you to the synagogues, and to rulers and authorities, be not anxious how or what you shall answer, or what you shall say;

Luke 21:14-15

Therefore, determine in your hearts not to meditate beforehand what you shall answer;

2 Corinthians 8:16

But thanks be to God, who put the same earnest care for you in the heart of Titus:

Philippians 2:13

for it is God, who, of his good pleasure, works in you both the will and the power to perform.

James 1:16-18

Be not deceived, my beloved brethren;

Treasury of Scripture Knowledge

Summary

The preparations of the heart in man, and the answer of the tongue, is from the LORD.

Bible References

Preparations

2 Corinthians 8:16
But thanks be to God, who put the same earnest care for you in the heart of Titus:
Philippians 2:13
for it is God, who, of his good pleasure, works in you both the will and the power to perform.
James 1:16
Be not deceived, my beloved brethren;

And

Matthew 10:19
But when they deliver you up, be not anxious how or what you shall speak; for that which you shall speak shall be given you in that hour:
Luke 12:11
When they bring you to the synagogues, and to rulers and authorities, be not anxious how or what you shall answer, or what you shall say;
Luke 21:14
Therefore, determine in your hearts not to meditate beforehand what you shall answer;