1) Matthew 6:1-4, Secret giving and Divine repayment.

2) Matthew 6:5-6, Private prayer and Divine repayment.

3) Matthew 6:18, Secret fasting and Divine repayment.

4) 1 Corinthians 4:4-5; Things hidden in darkness, motives of heart and
    Divine praise.

5) Romans 2:16, God will judge the secrets of men through Christ Jesus.

6) Colossians 3:22-24; Sincere heart, work from the soul, the Lord will
    reward.  Compare also 1 Peter 3:4 and Jeremiah 17:9-10.