Jesus Christ is the Shepherd, master of the flock - and we his lambs.
And Christ is the Lamb - lovely and knowable.
The Lamb of God grows from innocent, joyous dependence to unresisting sacrifice.
The Lion is God the Father - and without Christ He is a thing terrible, awesome, un-knowable, feared.
The Lion would naturally kill the Lamb; and indeed the Lamb is killed.
The Lamb rises glorious and lies down with the Lion.
The Lamb evokes our love, compassion, care - but a mortal Lamb cannot save us. The Lamb must be reborn, and rule with the Lion.
The Lamb becomes Shepherd...
It is only by our love for the reborn Lamb that we may have a proper and necessary relation with the Lion.