'Faith in Christ' in the Bible

Several days later Felix came with his wife Drusilla, who was a Jewess. He sent for Paul and listened to him talk about faith in Christ Jesus.

yet we know that a man is not justified [and placed in right standing with God] by works of the Law, but [only] through faith in [God’s beloved Son,] Christ Jesus. And even we [as Jews] have believed in Christ Jesus, so that we may be justified by faith in Christ and not by works of the Law. By observing the Law no one will ever be justified [declared free of the guilt of sin and its penalty].

and may be found in Him [believing and relying on Him], not having any righteousness of my own derived from [my obedience to] the Law and its rituals, but [possessing] that [genuine righteousness] which comes through faith in Christ, the righteousness which comes from God on the basis of faith.

for we have heard of your faith in Christ Jesus [how you lean on Him with absolute confidence in His power, wisdom, and goodness], and of the [unselfish] love which you have for all the saints (God’s people);

For even though I am absent [from you] in body, nevertheless I am with you in spirit, delighted to see your good discipline [as you stand shoulder to shoulder and form a solid front] and to see the stability of your faith in Christ [your steadfast reliance on Him and your unwavering confidence in His power, wisdom, and goodness].

and how from childhood you have known the sacred writings (Hebrew Scriptures) which are able to give you the wisdom that leads to salvation through faith which is in Christ Jesus [surrendering your entire self to Him and having absolute confidence in His wisdom, power and goodness].