SEV Biblia, Chapter 5:2
En esto conocemos que amamos a los hijos de Dios, cuando amamos a Dios, y guardamos sus mandamientos.
Clarke's Bible Commentary - 1 John 5:2
Verse 2. By this we know that we love the children of God] Our love of God's followers is a proof that we love God. Our love to God is the cause why we love his children, and our keeping the commandments of God is the proof that we love him.
John Gill's Bible Commentary
Ver. 2. By this we know that we are the children God , &c.] The Ethiopic version reads, by this know that we love God; which, in connection with what follows, makes a tautology, and is a proving idem per idem: whereas the apostle's view is to show when love to the saints is right; and that is, when we love God, and keep his commandments : love to the brethren may arise from such a cause, as may show that it is not brotherly love, or of a spiritual kind; it may arise from natural relation, or civil friendship, or from a benefit or favour received from them, and from some natural external excellency seen in them; and a man may do acts of love and kindness to the brethren, from what may be called good nature in himself, or with sinister views; but true love to the brethren springs from love to God: such who love the saints aright, and by which they may know they do so, they love them because they themselves love God, and in obedience to his command; they love them because they belong to God, and are the objects of his love; because his grace is wrought in them, and his image stamped upon them.
Matthew Henry Commentary
Verses 1-5 - True love for the people of God, may be distinguished from natura kindness or party attachments, by its being united with the love of God, and obedience to his commands. The same Holy Spirit that taugh the love, will have taught obedience also; and that man cannot trul love the children of God, who, by habit, commits sin or neglects know duty. As God's commands are holy, just, and good rules of liberty an happiness, so those who are born of God and love him, do not count the grievous, but lament that they cannot serve him more perfectly Self-denial is required, but true Christians have a principle whic carries them above all hinderances. Though the conflict often is sharp and the regenerate may be cast down, yet he will rise up and renew his combat with resolution. But all, except believers in Christ, ar enslaved in some respect or other, to the customs, opinions, or interests of the world. Faith is the cause of victory, the means, the instrument, the spiritual armour by which we overcome. In and by fait we cleave to Christ, in contempt of, and in opposition to the world Faith sanctifies the heart, and purifies it from those sensual lusts by which the world obtains sway and dominion over souls. It has the indwelling Spirit of grace, which is greater than he who dwells in the world. The real Christian overcomes the world by faith; he sees, in an by the life and conduct of the Lord Jesus on earth, that this world is to be renounced and overcome. He cannot be satisfied with this world but looks beyond it, and is still tending, striving, and pressin toward heaven. We must all, after Christ's example, overcome the world or it will overcome us to our ruin.
Greek Textus Receptus
εν 1722 τουτω 5129 γινωσκομεν 1097 5719 οτι 3754 αγαπωμεν 25 5719 τα 3588 τεκνα 5043 του 3588 θεου 2316 οταν 3752 τον 3588 θεον 2316 αγαπωμεν 25 5719 και 2532 τας 3588 εντολας 1785 αυτου 846 τηρωμεν 5083 5725
Vincent's NT Word Studies
2. By this (en toutw). Not by this or from this, as an inference (see on iv. 6), but in the very exercise of the sentiment toward God, we perceive. When (grov). More strictly, whenever. Our perception of the existence of love to our brethren is developed on every occasion when we exercise love and obedience toward God.
Keep (thrwmen). Read poiwmen do. So Rev. See on John iii. 21; 1 John iii. 4. The exact phrase poiein tav ejntolav to do the commandments, occurs only here. See on Apoc. xxii. 14.