In Bhagavad-gītā (4.11) the Lord says:

ye yathā māṁ prapadyante tāṁs tathaiva bhajāmy aham mama vartmānuvartante manuṣyāḥ pārtha sarvaśaḥ

“As devotees surrender unto Me, I reward them accordingly. Everyone follows My path in all respects, O son of Pṛthā.” Both Indra and Vṛtrāsura were certainly devotees of the Lord, although Indra took instructions from Viṣṇu to kill Vṛtrāsura. The Lord was actually more favorable to Vṛtrāsura because after being killed by Indra’s thunderbolt, Vṛtrāsura would go back to Godhead, whereas the victorious Indra would rot in this material world. Because both of them were devotees, the Lord awarded them the respective benedictions they wanted. Vṛtrāsura never wanted material possessions, for he knew very well the nature of such possessions. To accumulate material possessions, one must labor very hard, and when he gets them he creates many enemies because this material world is always full of rivalry. If one becomes rich, his friends or relatives are envious. For ekānta-bhaktas, unalloyed devotees, Kṛṣṇa therefore never provides material possessions. A devotee sometimes needs some material possessions for preaching, but the possessions of a preacher are not like those of a karmī. A karmī’s possessions are achieved as a result of karma, but those of a devotee are arranged by the Supreme Personality of Godhead just to facilitate his devotional activities. Because a devotee never uses material possessions for any purpose other than the service of the Lord, the possessions of a devotee are not to be compared to those of a karmī.