Jude 1:20

Building up

(εποικοδομουντες). Present active participle of εποικοδομεω, old compound with metaphor of a house (οικος), common in Paul (1 Corinthians 3:9-17; Colossians 2:7; Ephesians 2:20).On your most holy faith

(τη αγιωτατη υμων πιστε). For the spiritual temple see also 1 Peter 2:3-5. See πιστις (faith) in this sense (cf. Hebrews 11:1) in 2 Peter 1:5 with the list of graces added. A true superlative here αγιωτατη, not elative.Praying in the Holy Spirit

(εν πνευματ αγιω προσευχομενο). This is the way to build themselves up on their faith.