SB 11.4.22

bhūmer bharāvataraṇāya yaduṣv ajanmā
 jātaḥ kariṣyati surair api duṣkarāṇi
vādair vimohayati yajña-kṛto ’tad-arhān
 śūdrān kalau kṣiti-bhujo nyahaniṣyad ante
Synonyms: 
bhūmeḥ — of the earth; bhara — the burden; avataraṇāya — to diminish; yaduṣu — in the Yadu dynasty; ajanmā — the unborn Lord; jātaḥ — taking birth; kariṣyati — He will perform; suraiḥ — by the demigods; api — even; duṣkarāṇi — difficult deeds; vādaiḥ — by speculative arguments; vimohayati — He will bewilder; yajña-kṛtaḥ — the performers of Vedic sacrifices; atat-arhān — who are unfit to be so engaged; śūdrān — the low-class men; kalau — in the degraded Age of Kali; kṣiti-bhujaḥ — rulers; nyahaniṣyat — He will kill; ante — at the end.
Translation: 
To diminish the burden of the earth, the unborn Lord will take birth in the Yadu dynasty and perform feats impossible even for the demigods. Propounding speculative philosophy, the Lord, as Buddha, will bewilder the unworthy performers of Vedic sacrifices. And as Kalki the Lord will kill all the low-class men posing as rulers at the end of the Age of Kali.
Purport: 

It is understood that in this verse the description of the Lord’s appearance in the Yadu dynasty refers to the appearance of both Kṛṣṇa and Balarāma, who together removed the demoniac rulers who were burdening the earth. Śrīla Jīva Gosvāmī has pointed out that the description of the incarnations to deal with śūdrān, or low-class men, refers to both Buddha and Kalki. Those who misuse Vedic sacrifice to engage in gross sense gratification, such as the sinful killing of animals, are certainly in the category of śūdra, as are the so-called political leaders of Kali-yuga who perform many atrocities in the name of state management.