For the truth's sake (dia thn alhqeian). Repetition of the word, one of which John is very fond ( 1 John 1:6 , "the truth, as revealed by the Christ, and gradually unfolded by the Spirit, who is truth" (Brooke). Which abideth in us (thn menousan en hmin). See John 17:19 for "sanctified in truth" and 1 John 2:6 for abiding in Christ, and so it includes all who are in Christ. It shall be with us (meq hmwn estai). Confident assertion, not a mere wish. Note the order of the words, "With us it shall be" (estai future middle of eimi).