Sh. Muḥammad b. Ṣāliḥ al-ʿUthaymīn, may Allāh have mercy upon him, replied:

“Loving for the sake of Allāh means to not love a man except for the sake of Allāh, in that you see him engage in an abundance of worship, abundant charity, loving goodness, and hating evil; so you love him for that, not because he is a close relative of yours, or a friend, or rich, or poor etc.

Hating for the sake of Allāh means to hate him [a person] because he is disobedient towards Allāh the Almighty and Exalted, and is not steadfast upon the command of Allāh, not because of personal enmity between you and him but because he neglected Allāh’s rights.”

Source: Fatāwá Nūr ʿalá al-Darb (1: 645, no. 512).