The phrase "consider the lilies of the field" is from Matthew 6:28–29, part of Jesus' teaching in the Sermon on the Mount that his hearers not be anxious about clothing.
28 And why take ye thought for raiment? Consider the lilies of the field, how they grow; they toil not, neither do they spin: 29 And yet I say unto you, That even Solomon in all his glory was not arrayed like one of these.
In the surrounding passage (Matthew 6:25–34), Jesus points to the lilies and to the grass of the field as examples in his argument that his hearers should not be anxious about food or clothing. Read the full chapter at Matthew 6.