Who did Jesus say would have a harder time entering heaven than a camel going through the eye of a needle?

A rich man

Then said Jesus unto his disciples, Verily I say unto you, That a rich man shall hardly enter into the kingdom of heaven.

And again I say unto you, It is easier for a camel to go through the eye of a needle, than for a rich man to enter into the kingdom of God. Matthew 19:23-24

(See also Mark 10:23-25)