Biblically, the faithful are- those who are able, [by the Holy Spirit alone] to spiritually, by their own understanding mentally, and by their own confession verbally, profess and know Christ as their Lord.
The “seed” of believers is Christ Himself, just as He is the Seed of [the faith of] Abraham. For it is from this Seed alone, that the life which the believer lives deeply rooted in their dependence upon Him, [by faith and not by sight,] produces Righteous Fruit, upheld forever by their Strong Root, Who promises healthy growth and protection to His very own blood-bought Crop. Christ is the Seed, Strong Root, Sure and Steady Anchor- Who sustains His Crop, the Church.
Christ did not merely inaugurate “a” new covenant, (a mere different or “the next” covenant) but He is “THE” New Covenant, the ONLY Covenant, the FINAL Covenant; in Whom, all who Trust in Him, find their rest and peace.
NONE.. who dwell [in] the Shelter of the Most High (when plummeted by the storms of their enemies), or, who find rest in the Shadow of His Wing (from the Just heat of His reprimanding due them for their sin) [are there without], and [only there by] Grace alone, through Faith alone, in Christ alone, according to Scripture alone, (for their good) and to the Praise and Glory of God alone.

ALSO SEE:
Genesis 12:7
Jeremiah 17:7-8; 31-34
Psalm 1:3; 92:12                                                                                             Romans 8:28-31
2 Corinthians 5:7
Galatians 3:1-29
Colossians 2:6-7
Hebrews 8:1-13
Revelation 14:12