CC Madhya 22.60

ei ājñā-bale bhaktera ‘śraddhā’ yadi haya
sarva-karma tyāga kari’ se kṛṣṇa bhajaya
Synonyms: 
ei ājñā-bale — on the strength of this supreme order of the Supreme Personality of Godhead; bhaktera — of the devotees; śraddhā — faith; yadi — if; haya — there is; sarva-karma — all other activities, material and spiritual; tyāga kari’ — leaving aside; se — he; kṛṣṇa bhajaya — serves Lord Kṛṣṇa.
Translation: 
“If the devotee has faith in the strength of this order, he worships Lord Kṛṣṇa and gives up all other activities.