Pistis christou: whose faith?

In the following examples, while "faith in Jesus" is not implausible, a better translation is the "faithfulness of Jesus." In other words, Paul underscores the significance of Jesus's faithfulness and his grace in which God calls people. 

• διὰ πίστεως Ἰησοῦ Χριστοῦ (Rom 3:22): through Jesus Christ's faith
• ἐκ πίστεως Ἰησοῦ (Rom 3:26): from Jesus's faith
• διὰ πίστεως Χριστοῦ Ἰησοῦ (Gal 2:16): through Christ Jesus's faith
• ἐν πίστει ζῶ τῇ τοῦ Υἱοῦ τοῦ Θεοῦ (Gal 2:20): I will live by (in) the faith of the Son of God
• ἐκ πίστεως Ἰησοῦ Χριστοῦ (Gal 3:22): from Jesus Christ's faithfulness

*ἐκ πίστεως Ἀβραάμ (Rom 4:16): from Abraham's faith
*If Paul meant "faith in Jesus," he would have used the prepositional phrase: pistis en christo, which is found in the Deutero-Pauline and Pastoral letters: Col 1:4; 1 Tim 1:4; 3:13; 2 Tim 1:13; 3:15.