“Today, if you hear his voice, do not harden your hearts.” The writer of Hebrews is quoting David, “For he is our God and we are the people of his pasture, the flock under his care. Today, if you hear his voice, do not harden your hearts...” We can better understand this important scriptural phrase by visualizing the relationship between a shepherd and his sheep. A shepherd uses his voice to care for his flock. His calls lead them to pasture, water and shelter. In the same way, Jesus calls for souls to follow him.