actually, *why *did Jesus even say that to monotheistic Jews?
being
greater than does not mean in nature since the **Word is God **as John says

an example illustrates this point:
“I tell you the truth: Among those born of women there has not risen anyone **greater **than John the Baptist; yet he who is least in the kingdom of heaven is **greater **than he.” Matthew 11:11
John being greater than all those born of women does not mean that the rest were less human than John or that they were inferior to John in nature. Here, it means that John was greater in position and rank.
“For who is the greater, one who reclines at table or one who serves? Is it not the one who reclines at table? But I am among you as the one who serves.” Luke 22:27
“Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but made himself nothing, taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.” Philippians 2:5-8