Albert Barnes Commentary 1 John 5:14

"And this is the boldness which we have toward him, that, if we ask anything according to his will, he heareth us:" — 1 John 5:14 (ASV)

And this is the confidence that we have in him. Margin: concerning. Greek, "towards him," or in respect to him—pros auton. The confidence referred to here is that which relates to the answer to prayer. The apostle does not say that this is the only thing regarding which there is to be confidence in him, but that it is one which is worthy of special consideration. The sense is, that one of the effects of believing on the Lord Jesus (1 John 5:13) is that we have the assurance that our prayers will be answered.

That, if we ask any thing according to his will, he heareth us. This is the proper and the necessary limitation in all prayer. God has not promised to grant anything that shall be contrary to his will, and it could not be right that he should do it. We ought not to wish to receive anything that should be contrary to what he judges to be best. No one could hope for good who should esteem his own wishes to be a better guide than the will of God; and it is one of the most desirable of all arrangements that the promise of any blessing to be obtained by prayer should be limited and bounded by the will of God. The limitation here, "according to his will," probably implies the following things:

1. In accordance with what he has declared that he is willing to grant. Here the range is large, for there are many things which we know to be in accordance with his will, if they are sought in a proper manner: the forgiveness of sins; the sanctification of the soul (1 Thessalonians 4:3); comfort in trial; the needful supply of our wants; grace that we may do our duty; wisdom to direct and guide us (James 1:5); deliverance from the evils which beset us; the influences of his Spirit to promote the cause of religion in the world; and our final salvation. Here is a range of subjects of petition that may gratify the largest wishes of prayer.
2. The expression, "according to his will," must limit the answer to prayer to what he sees to be best for us. Of that we are not always good judges. We never perceive it as clearly as our Maker does, and in many things we might be wholly mistaken. Certainly, we ought not to desire to be permitted to ask anything which God would judge not to be for our good.
3. The expression must limit the petition to what it will be consistent for God to bestow on us. We cannot expect that he will work a miracle in answer to our prayers; we cannot ask him to bestow blessings in violation of any of the laws which he has ordained, or in any other way than that which he has appointed. It is better that the particular blessing should be withheld from us than that the laws which he has appointed should be disregarded. It is better that an idle person should not have a harvest, though he should pray for it, than that God should violate the laws by which he has determined to bestow such favours as a reward of industry and work a special miracle in answer to a lazy person's prayers.
4. The expression, "according to his will," must limit the promise to what will be for the good of the whole. God presides over the universe; and though in him there is an infinite fullness, and he regards the wants of every individual throughout his immense empire, yet the interests of the whole, as well as of the individual, are to be consulted and regarded. In a family, it is conceivable that a child might ask for some favour whose bestowal would interfere materially with the rights of others, or be inconsistent with the good of the whole, and in such a case a just father would of course withhold it. With these necessary limitations, the range of the promise in prayer is ample; and, with these limitations, it is true beyond a question that he does hear and answer prayer.