1 John 3:21
21. Beloved—There is no "But" contrasting the two cases, 1Jo 3:20, 21, because "Beloved" sufficiently marks the transition to the case of the brethren walking in the full confidence of love (1Jo 3:18). The two results of our being able to "assure our hearts before Him" (1Jo 3:19), and of "our heart condemning us not" (of insincerity as to the truth in general, and as to LOVE in particular) are, (1) confidence toward God; (2) a sure answer to our prayers. John does not mean that all whose hearts do not condemn them, are therefore safe before God; for some have their conscience seared, others are ignorant of the truth, and it is not only sincerity, but sincerity in the truth which can save men. Christians are those meant here: knowing Christ's precepts and testing themselves by them.
1 John 5:14
14. the confidence—boldness (1Jo 4:17) in prayer, which results from knowing that we have eternal life (1Jo 5:13; 1Jo 3:19, 22).
according to his will—which is the believer's will, and which is therefore no restraint to his prayers. In so far as God's will is not our will, we are not abiding in faith, and our prayers are not accepted. ALFORD well says, If we knew God's will thoroughly, and submitted to it heartily, it would be impossible for us to ask anything for the spirit or for the body which He should not perform; it is this ideal state which the apostle has in view. It is the Spirit who teaches us inwardly, and Himself in us asks according to the will of God.