We are saved through faith alone, but the object of our saving faith is Christ alone. More precisely, we are saved entirely on the exclusive identity of Christ. The perfect and complete, all-sufficient work of Christ and our sole mediator and representative.
This means that Christ is the subject, the author, and the medium of our faith. We have all we need now and forever found in Christ. Trust in the exclusivity of Christ for salvation and trust in the sufficiency of Christ for salvation are necessary to understand what it means to trust in Christ alone for salvation. Knowledge about the facts of Jesus are not enough, since people know God’s decree yet do not obey (Rom 1:32). Even the demons know who God is and the shudder (James 2:19).
So trust, dependence on this exclusive all-sufficient Savior Jesus, saving faith is trust in Jesus Christ as a living being for the forgiveness of sins and eternal life with God. The Bible uses the word trust in its relational sense in order to express how trusting in Christ alone is necessary for salvation. John 1:12 speaks of all who received him, like one receives a guest, or Jesus speaks of coming to Him (Matt 11:28-30).
Trust also grows, the more we get to know a person the more fully we put our trust in Him. At the beginning having a reliable testimony of someone and trusting in that testimony is the start of a relationship. With Christ we are given Scripture as a reliable testimony in which we gain the true knowledge of Jesus Christ (Rom 10:17).
By trusting in God, we are also turning from sin. Repentance is that combined with trust in God and turning away from our sins (Acts 3:19; 8:22; 26:18). As it is written in Mark 1:15 says repent and believe in the gospel. This behavior should be reflected in obedience to Him and His word (Acts 27:25). Trusting is also a continual process.
We are to grow in godliness and learning and pursuing Jesus Christ learning His character. Our trust in Jesus is a personal and relational trust, it is in the exclusivity of Jesus, the sufficiency of Jesus. The exclusivity of Jesus found in Him being the only way (John 14:6). The London Baptist Confession of Faith writes it this way; “Faith thus receiving and resting on Christ and His righteousness, is the alone instrument of justification; yet is not alone in the person justified, but is ever accompanied with all other saving graces, and is no dead faith but works by love.”
The instrumental word as it relates to the question of trust, is resting on Christ. Nothing else leads to salvation, only resting, or more clearly trusting, on the promises of God that He makes through Christ. Only by God’s grace are we saved through faith in Christ Jesus.