Colossians 1:1

1 Παῦλος ἀπόστολος Χριστοῦ Ἰησοῦ διὰ θελήματος θεοῦ καὶ Τιμόθεος ὁ ἀδελφὸς

Παῦλος -  noun Nom sing. masc.   "Paul" (nominative absolute  aka. Independent Nominative)

ἀπόστολος -noun  nom sing. masc.  (simple apposition) "an apostle"

Χριστοῦ Ἰησοῦ - noun Genitive sing. masc.  2x  "of Christ Jesus"  (genitive of possession)

διὰ  -  prep. with the genative ③ marker of instrumentality or circumstance whereby someth. is accomplished or effected, by, via, through^[1]ⓓ of efficient cause via, "through"

θελήματος - noun Genitive sing. neuter  "desire, wish" (genitive after the prep.)

θεοῦ- noun genitive sing. masc. "of God" (subjective genitive)

καὶ -  conj. "and"  (copulative)

Τιμόθεος - Noun nom. sing. masc.  "Timothy" (nominative absolute)

ὁ ἀδελφὸς  - noun nom. sing. masc.  with the definite article  "the brother"  (simple apposition)

Translation- "Paul an apostle of Christ Jesus through the will of God and Timothy the brother."

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^[1] Arndt, W., Danker, F. W., & Bauer, W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed.) (224). Chicago: University of Chicago Press.