Read Hebrews 3 today.

This chapter includes a comparison between Jesus and Moses, and the declaration the Jesus is superior to Moses. It also includes numerous admonitions to not harden our hearts by turning away from God.
What kind of experiences have you had with someone who had a hard heart? In what kind of circumstances are you tempted to harden your heart toward other people? Toward God? What steps might you take to keep your heart soft toward God?
Hebrews 3:12-15 NLT
Be careful then, dear brothers and sisters. Make sure that your own hearts are not evil and unbelieving, turning you away from the living God. [13] You must warn each other every day, while it is still “today,” so that none of you will be deceived by sin and hardened against God. [14] For if we are faithful to the end, trusting God just as firmly as when we first believed, we will share in all that belongs to Christ. [15] Remember what it says: “Today when you hear his voice, don’t harden your hearts as Israel did when they rebelled.”