Hebrews 12:18-19, 21-24 / Mark 6:7-13
If we have to use analogies to describe the OT and the NT, then the OT can be said to be like the radio and the NT is like the television.
The OT let us hear the Word of God. The NT not only let us hear the Word of God but also let us see the Word of God in the person of Jesus.
The 1st reading gives us another dimension as well as another comparison between the OT and the NT.
In the OT the blood of Abel cries out for vengeance. In the NT, the blood of Christ cries out and pleads more instantly for mercy.
And it is mercy that has restored us to heaven and it has also given us the status as the "first-born son" and a citizen of heaven.
All because Christ came and poured out His blood so that we can be saved by the mercy of God.
And that was what Jesus sent His disciples to preach - repentance. So that we can be saved.
The blood of Christ is pleading to us to repent and may it not be pleading in vain.
Yes, Christ is pleading for us to repent, because He would rather go through hell to save us than to go to heaven without us.