In Islam ” love each other” is not just words but action where you wish the other good and help them as if you do it for your self even the Prophet link it to faith The Messenger of Allah PBUH said: “By the One in Whose hand is the soul of Muhammad, none of you has believed until he loves for his brother what he loves for himself of goodness.”
Those are not just words… that why they reflect a true belief in Allah as the prophet PBUH said “Love for people what you love for yourself, and you will be a (true) believer”
if you help the person and he/she gets a better job than yourself… that is a sign of strong belief in monotheism because you know that God is the giver
إِنَّ اللَّهَ هُوَ الرَّزَّاقُ ذُو الْقُوَّةِ الْمَتِين
” Indeed, it is Allah who is the [continual] Provider, the firm possessor of strength. (51:58) “
and you are not worried about the effect of your help if that person became better or in a higher position because it is you bettering yourself and cleaning it from Jealousy.
That why Allah mentions that behaviour of people of Madinah when Muslim of Makkah migrated to them without money nor home to stay they share all of what they have equally aiming to please Allah
وَالَّذِينَ تَبَوَّءُوا الدَّارَ وَالْإِيمَانَ مِنْ قَبْلِهِمْ يُحِبُّونَ مَنْ هَاجَرَ إِلَيْهِمْ وَلَا يَجِدُونَ فِي صُدُورِهِمْ حَاجَةً مِمَّا أُوتُوا وَيُؤْثِرُونَ عَلَىٰ أَنْفُسِهِمْ وَلَوْ كَانَ بِهِمْ خَصَاصَةٌ ۚ وَمَنْ يُوقَ شُحَّ نَفْسِهِ فَأُولَٰئِكَ هُمُ الْمُفْلِحُونَ
”Those who came to the city and to faith before them, love those who take refuge with them, and do not feel for themselves any need for what is given them, and give them preference over themselves even if they are indigent. Whoever preserves himself from his own greed will be prosperous. (59:9)”
In Islam love others is not a slogan is part of faith and its word followed by actions