6 Therefore it is also contained in the Scripture, “Behold, I lay in Zion a chief cornerstone, elect, precious, and he who believes on Him will by no means be put to shame.” 7 Therefore, to you who believe, He is precious; but to those who are disobedient, “The stone which the builders rejected has become the chief cornerstone,” 8 and “A stone of stumbling and a rock of offense.” They stumble, being disobedient to the word, to which they also were appointed. (1 Peter 2:6–8, NKJV)
Jesus is compared to two very different stones in this passage. First, He is the chief cornerstone from whom the temple of God, the church, has been measured and built (1 Peter 2:4-6; Matthew 16:18). Chosen by God for His preciousness, believers who trust Him will not be put to shame, for they are “living stones” in God’s spiritual house (1 Peter 2:4-5). Second, Jesus is a stone of stumbling and rock of offense to those who reject Him as the chief cornerstone. Refusing to put their faith in Him, they disobey His word. The disobedient are set (appointed) to stumble over Christ in their unbelief. Christ has been set as the chief cornerstone of God’s house. By believing and obeying His word, He will not be a rock of offense over which you fall, but the precious, living stone who gives life to you (1 Peter 2:4-5).
24 Now to Him who is able to keep you from stumbling, and to make you stand in the presence of His glory blameless with great joy, 25 to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion and authority, before all time and now and forever. Amen. (Jude 24–25, NASB95)
Since God is able to “keep” (preserve) you stumbling, the possibility of stumbling necessarily exists (cf. Gal. 5:7). He will stand you blameless before Him, when you build up yourselves in the faith, pray in the Spirit, and keep (preserve) yourselves in the love of God (Jude 20-21). Eternal life, while provided by the power and authority of “the only God our Savior,” is not unconditional. “He who believes and is baptized will be saved” (Mk. 16:16); Belief and baptism are conditions that one must meet in order to be saved. “Therefore, brethren, be even more diligent to make your call and election sure, for if you do these things you will never stumble; for so an entrance will be supplied to you abundantly into the everlasting kingdom of our Lord and Savior Jesus Christ” (2 Pet. 1:10-11). Note the word “if” – “if you do these things…” That’s a condition the Christian must meet in order to have confidence of gaining entrance into the eternal kingdom. God has the “dominion and authority” to save you. He calls on you to be loyal to Him by remaining steadfast and faithful.