Being faithful means following through on a promise you've made. "The Lord is not slow about His promise . . . not wishing for any to perish but for all to come to repentance" (2Pe 3:9). "He who promised is faithful" (Heb 10:23). However, we must "hold fast the confession of our hope without wavering" (:23). By faith Sarah had Isaac because "she considered Him faithful who had promised" (11:11). "Faithful is He who calls you, and He also will bring it to pass" (1Th 5:24). It is the way God is. It is his name. John said, "I saw heaven opened, and behold, a white horse, and He who sat on it is called Faithful and True" (Rev 19:11). "He remains faithful, for He cannot deny Himself" (2Ti 2:13). He "made heaven and earth, the sea and all that is in them; who keeps faith forever" (Ps 146:6). "In the heavens You will establish Your faithfulness" (Ps 89:2). "The witness in the sky is faithful" (89:37).
You are faithful when a friend knows he can depend on you for help. She should be "faithful to her husband" (1Ti 5:9 NIV). "'Know therefore that the Lord your God, He is God, the faithful God who keeps His covenant'" (Dt 7:9). She is "your wife by covenant" (Mal 3:14) so "do not break faith" (:15 NIV). "If we are faithless, He remains faithful, for He cannot deny Himself" (2Ti 2:13). "'Listen, that you may live; and I will make an everlasting covenant with you, according to the faithful mercies shown to David'" (Isa 55:3). "All the paths of the Lord are lovingkindness and truth to those who keep His covenant and His testimonies" (Ps 25:10). Deuteronomy 7:9 also says God "'keeps His lovingkindness to a thousandth generation with those who love Him and keep His commandments.'" Faith and love go together. "'My faithfulness and My lovingkindness will be with him'" (Ps 89:24). "The Lord's lovingkindnesses indeed never cease, for His compassions never fail. They are new every morning; great is thy faithfulness" (La 3:22-23).
God's faithfulness is manifested. "I will exalt You, I will give thanks to Your name; for You have worked wonders, plans formed long ago, with perfect faithfulness" (Isa 25:1). "His work is perfect, for all His ways are just; a God of faithfulness and without injustice, righteous and upright is He" (Dt 32:4). "The word of the Lord is upright, and all His work is done in faithfulness" (Ps 33:4). We are the recipient of God's work, but it is a two-way street. "Those also who suffer according to the will of God shall entrust their souls to a faithful Creator in doing what is right" (1Pe 4:19). "My eyes shall be upon the faithful of the land, that they may dwell with me; He who walks in a blameless way is the one who will minister to me" (Ps 101:6). Therefore "the Lord preserves the faithful" (Ps 31:23).