When Jesus calls upon us to love our neighbours as ourselves in Mark 12:31, he quotes Leviticus 19:18
'Do not seek revenge or bear a grudge against anyone among your people, but love your neighbour as yourself.'
He also further elaborates on the Mosaic commandment in a challenging way.
'Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you. If someone slaps you on one cheek, turn to them the other also. If someone takes your coat, do not withhold your shirt from them. Give to everyone who asks you, and if anyone takes what belongs to you, do not demand it back. (Luke 6:27b-3o)
His concise summary offers the 'golden rule' for all ethical behaviour. It makes concrete the meaning of 'love your neighbour as yourself'.
'Do to others as you would have them do to you.'
What do we want most? How do we prefer others to treat us, according to our desires or according to what we feel we deserve? What we want may be unrealistic, and what we expect can equally be unrealistic, for in a fallen world, we may not have been loved as much as we needed nor have been as loving to others as we ought to be.
Illusions about ourselves are a product of estrangement from God. God loves us, we have imperfect ideas of God and what love means, whether God's love or the love of others. We learn of God's love through the story of Jesus, and in turning to God, start to learn how to see ourselves in the same way as he does. We pray, in order to shed any illusions we may have about God or ourselves. Many ideas we have about God and ourselves fall far short of the reality.
Much of Jesus's ministry to poor, needy and broken people is about restoring their inner peace and self-confidence, by honestly valuing the faith they have, and respecting their gifts. Nothing is gained by self exaggeration or promotion. We are asked to be honest and realistic about ourselves. He responds compassionately to the pleas of a man who honestly struggles to trust, who says to him
'Lord I believe, help thou my unbelief' (Mark 9:24)
Such is an example of genuine humility, not pretending to believe more than we truthfully know we do. Jesus reassures us, however:
'Everyone who exalts himself will be humbled, but the one who humbles himself will be exalted' (Luke 18:14)
There is no time at which the tax collector's prayer is not relevant in helping to refine us in honesty, whether we are broken by failure, or exulted by success.
'Lord have mercy upon me a sinner.'