The Pharisees must have been smarting from their verbal defeat by Jesus. Jesus had shown that their evil explanation of His miracles – that He was casting out demons by the power of Satan – was both absurd and contradictory. His arguments should have moved them to reconsider their position, but they did not, of course. They hated Jesus, so rather than altering their views, they merely came at Hm from another direction, demanding a miraculous sign.
His steadfast love, His covenantal, loyal, merciful love, His committed love, His complete forgiveness of all our sins is so staggering and so vast that it can only be explained by two illustrations of infinity. These are the most perfect illustrations you could find in human language, which isn’t surprising since the Holy Spirit is the Author.