These hadiths are all in explaining love, and that a person should have his love for Allah and in Allah.

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful:
These hadiths are all in explaining love, and that a person should have his love for Allah and in Allah. In this hadith mentioned by the author (may Allah have mercy on him), where the Prophet (peace and blessings be upon him) said:
In this is evidence that love is part of the perfection of faith, and that the faith of a servant is not complete until he loves his brother. And among the causes of love is that a person should spread the greeting of peace among his brothers, meaning he should display it and declare it, and greet the believers he meets, whether he knows them or not. For this is among the causes of love. Therefore, if a man passes by you and greets you, you will love him. And if he turns away, you will dislike him, even if he is the closest person to you.
So what is obligatory for a person is to strive with every cause that necessitates affection and love among the Muslims. For it is not reasonable, nor is it customary, for a person to cooperate with someone he does not love. And cooperation in good and cooperation in righteousness and piety is not possible except through love. For this reason, love for Allah is part of the perfection of faith.
And in the hadith of Mu'adh (may Allah be pleased with him): the Prophet (peace and blessings be upon him) informing him that he loves him. This indicates that it is from the Sunnah, if you love a person, to say: I love you. This is because of what this word contains of casting love into his heart. For when a person knows that you love him, he loves you, even though hearts have recognition and affinity even if tongues do not speak.
And as the Prophet (peace and blessings be upon him) said: But if a person says it with his tongue, then this increases love in the heart. So you say: I love you for Allah's sake.
And in his statement (peace and blessings be upon him): Meaning: at the end of every prayer. For the "dabr" (end) of a thing is like the end of an animal. And this hadith has come with a clear wording indicating that a person says it before the taslim. So he says before the salam: And success is from Allah.