Jesus IS our slain Lamb. But He is also called the Lion in Revelation.
"But one of the twenty-four elders said to me," Stop weeping! Look, the Lion of the tribe of Judah, the heir to David's throne, has won the victory. He is worthy to open the scroll and it's seven seals." (Rev. 5:5)
He is BOTH our Lion and our Lamb. Paul could not find anyone worthy to open the scroll. But one of the elders told him to look, the Lion within the Lamb was worthy.
Jesus comes to us as a lamb, slain. But has the mighty power of a lion. Not only did He have the power to tear open the seven seals but He also wants to tear open the seal over our hearts. Or our relative's, enemie's, neighbor's, friend's...
"Worthy is the Lamb,who was slain, to receive power and wealth and wisdom and STRENGTH and honor and glory and praise!"