One can justifiably say that this expression of God's faithfulness is the pivot upon which turns His whole purpose for humanity. God calls and then through His goodness leads us to repentance (Romans 2:4). I John 1:9 then adds, "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness."
Since Christ has come and died that we might be pardoned and cleansed, God's faithfulness is part of His grace. He would not be faithful to His promises, His past acts in Christ's works, or His calling that has sounded in our ears unless, when we obeyed the call and confessed, He allowed us to enter into the full possession of His pardoning grace. In other words, our forgiveness and cleansing, the receiving of favor from Him, is a product of His faithfulness.
God's faithfulness in these areas has far-reaching, practical ramifications for us. That God is faithful means that His character is unchangingly consistent. The unalterable structure of the universe consists of both justice and forgiveness. God never acts in contradiction of Himself, and in all experiences we may depend on Him to be unalterably just and forgiving toward us. Because He is faithful, He can be the central and most important object of our faith. Could we trust a god if we were never sure what he would do?