Jesus is the expiation for our sins
Et in hoc cognoscimus quoniam novimus eum: si mandata eius servemus.
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See Acts 4:32, 1 Cor. 1:10, 2 Cor. 13:11, Phil. 1:27, 4:2. “An appeal to share a common outlook on Christian living and a common vision for Christian unity. This ideal can become real only if humility and service take the place of pride and selfishness among them.” (ISB, CCC 2842)
(1) Latin Fathers: “something seized”, Jesus didn’t have to aggressively acquire it, because it belonged to him by nature and right. (2) Greek Fathers: “something held fast”, Jesus didn’t cling to it because he could not lose it. (3) Others: “something to be seized that is not already possessed”, Jesus (as a man) did not try to be an equal to God. (4) Another: “something to be exploited for personal gain”, Jesus was not like the ambitious world rulers who believed they had divine dignity. (cf. ISB)
Consider Also Genesis 3 (Adam and Eve “grasping” for equality with God).
Jesus emptied and humbled himself, being a servant to others, being obedient to God. We should think of the needs of others, being humble and not selfish, discerning the mind of God for us.
He was “in the form of God” but “emptied himself”, “taking the form of a servant”, born “in the likeness of men”. He pre-existed creation. He was “in the form of God” before the Incarnation. See Col. 1:15-16, 2:9, and Heb. 1:2b-3a.
Kenosis means “empty out” or “render void”. He didn’t lose his divinity, but his glory was concealed by his flesh (cf. Isaiah 52:13-53:12). He accepted human restrictions and limitations (cf. Luke 2:52). (cf. CCC 472)
Lord, which in Greek is kurios (“kyrie”). This was used to translate Adonai in the O.T., which is rendered as LORD in English. Adonai was used in place of YHWH, the “tetragrammaton”, which was how Yahweh (we think) was written by the Jews. Because Jesus is called “Lord”, this is a statement of his divinity, his unity and equality with God the Father.
Even further, “Lord” was the title that a secular ruler (like Caesar) would take for himself. But there is only one Lord, and that is Jesus. Only by the Holy Spirit can we confess that “Jesus is Lord” (1 Cor. 12:3). (cf. CCC 446-450)
Paul is making Christ the center of this prophecy, making Jesus the divine Lord destined to be revered by all creation. There is no other God and no other Lord. (cf. IBS)
Obedience. God can give us rules and tell us to follow them, but in God the Son we see God teaching us how to obey Him.