As has just been said:
"Today, if you hear his voice,
do not harden your hearts
as you did in the rebellion."

Here the writer of Hebrews quotes from Psalm 95. In doing so he gives us a sense of the immediacy and urgency of the voice of God. Today, not tomorrow, not at some later date or some time in the future when things are more convenient, the author says; "today." He means it. Today, when you hear God's voice, when he speaks to you, do not harden your hearts as was done in the rebellion. "The rebellion," was God's understanding of how the people of God responded to him in the desert; after he had led them out of slavery. Though he had displayed his power so clearly and in order to redeem them; rather than trusting, believing and putting their faith in him they chose instead to rebel, to harden their hearts and go into a place of sustained whining and complaining. But God says; no. Instead when God speaks, listen and obey. In that there is, "rest." Rest in the sense of ultimately if we do not harden our hearts we will enter the promised land of the new heavens and the new earth, but also the "rest" of knowing and walking in the will of God.

What is God saying to you? Today, hear his voice, listen and obey. In that there is rest.

Grace and peace from Marcus