In The Lamb by William Blake the poem shows a strong metaphor of the 'little lamb' representing jesus and how he came to be. At first, however, it is not very obvious what the poem if refering to, until "For he calls himself a Lamb"(Line 14), this line clearly displays a referense to God starting with the fact that the lamb in the line is capatilized indicating a proper noun, not the common lamb as first perceived. Furthering this, seeing as the object is called the little lamb, along with the reference to the Lamb or God, you can assume that this little lamb would be the son of God, Jesus Christ.
In The Tyger by William Blake, this poem directly displays Hades, or the Devil, as the Tyger. It further extends the metaphor of God the creator of Jesus in The Lamb when he says "Did he who made the Lamb make thee?"(Line 20) Blake is now questioning why God who made something so amazing and wonderful as Jesus would create something of complete opposition like the Devil.