2 Corinthians 4:1
Therefore, since it is by God's mercy that we are engaged in this ministry, we do not lose heart.
2 Corinthians 4:16
Therefore, as I said, we do not lose heart. No, even though outwardly we are wasting away, yet inwardly we are being renewed day by day.
Hebrews 12:3
Weigh well the example of him who had to endure such opposition from 'men who were sinning against themselves,' so that you should not grow weary or faint-hearted.
Hebrews 12:5
and you have forgotten the encouraging words which are addressed to you as God's Children-- 'My child, think not lightly of the Lord's discipline, do not despond when he rebukes you;