sermon on the mount: "So be perfect, just as your heavenly Father is perfect."

In the “Sermon on the Mount” (Matthew, CHAPTER 5 | USCCB) the theme of righteousness is prominent, and even at this early stage of the ministry the note of opposition is struck between Jesus and the Pharisees, who are designated as “the hypocrites” (Mt 6:2, 5, 16). The righteousness of his disciples must surpass that of the scribes and Pharisees; otherwise, in spite of their alleged following of Jesus, they will not enter into the kingdom of heaven (Mt 5:20). Righteousness means doing the will of the heavenly Father (Mt 7:21), and his will is proclaimed in a manner that is startling to all who have identified it with the law of Moses. The antitheses of the Sermon (Mt 5:21–48) both accept (Mt 5:21–30, 43–48) and reject (Mt 5:31–42) elements of that law, and in the former case the understanding of the law’s demands is deepened and extended. The antitheses are the best commentary on the meaning of Jesus’ claim that he has come not to abolish but to fulfill the law (Mt 5:17). What is meant by fulfillment of the law is not the demand to keep it exactly as it stood before the coming of Jesus, but rather his bringing the law to be a lasting expression of the will of God, and in that fulfillment there is much that will pass away. Should this appear contradictory to his saying that “until heaven and earth pass away” not even the smallest part of the law will pass (Mt 5:18), that time of fulfillment is not the dissolution of the universe but the coming of the new age, which will occur with Jesus’ death and resurrection. While righteousness in the new age will continue to mean conduct that is in accordance with the law, it will be conduct in accordance with the law as expounded and interpreted by Jesus (cf. Mt 28:20, “…all that I have commanded you”). 

Matthew, THE GOSPEL ACCORDING TO MATTHEW | USCCB 

Jesus teaches his followers to pray to the Father to "forgive us our sins as we forgive those who sin against us" and "Your kingdom come, Your will be done, on earth as it is in heaven" (Matthew 6: 5-15).

"Be perfect, just as your heavenly Father is perfect." Matthew 5:48 

https://www.biblestudytools.com/bible-study/topical-studies/truths-to-know-about-the-righteousness-of-god.html

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attribution: James Tissot, Public domain, via Wikimedia Commons