Because this brahmana (who was seized by King Kalmasapada) was actually qualified and was also engaged in brahminical activities (brahma-karma (BG 18.42)), killing him would be a greatly sinful act, and the brahmana's wife requested that he not be killed

Expressions researched:
"Because this brāhmaṇa was actually qualified and was also engaged in brahminical activities (brahma-karma" |"killing him would be a greatly sinful act, and the brāhmaṇa's wife requested that he not be killed"

Srimad-Bhagavatam

SB Canto 9

Not only must a brāhmaṇa be qualified, but he must also engage in actual brahminical activities. Simply to be qualified is not enough; one must engage in a brāhmaṇa's duties. The duty of a brāhmaṇa is to know the paraṁ brahma, Kṛṣṇa (paraṁ brahma paraṁ dhāma pavitraṁ paramaṁ bhavān (BG 10.12)). Because this brāhmaṇa was actually qualified and was also engaged in brahminical activities (brahma-karma (BG 18.42)), killing him would be a greatly sinful act, and the brāhmaṇa's wife requested that he not be killed.

SB 9.9.29, Translation and Purport

Here is a learned, highly qualified brāhmaṇa, engaged in performing austerity and eagerly desiring to worship the Supreme Lord, the Supersoul who lives within the core of the heart in all living entities.

The wife of the brāhmaṇa did not regard her husband as a superficial brāhmaṇa who was called a brāhmaṇa merely because he was born of a brāhmaṇa family. Rather, this brāhmaṇa was actually qualified with the brahminical symptoms. Yasya yal lakṣaṇaṁ proktam (SB 7.11.35). The symptoms of a brāhmaṇa are stated in the śāstra:

śamo damas tapaḥ śaucaṁ

kṣāntir ārjavam eva ca

jñānaṁ vijñānam āstikyaṁ

brahma-karma svabhāvajam

"Peacefulness, self-control, austerity, purity, tolerance, honesty, wisdom, knowledge, and religiousness-these are the qualities by which the brāhmaṇas work." (BG 18.42) Not only must a brāhmaṇa be qualified, but he must also engage in actual brahminical activities. Simply to be qualified is not enough; one must engage in a brāhmaṇa's duties. The duty of a brāhmaṇa is to know the paraṁ brahma, Kṛṣṇa (paraṁ brahma paraṁ dhāma pavitraṁ paramaṁ bhavān (BG 10.12)). Because this brāhmaṇa was actually qualified and was also engaged in brahminical activities (brahma-karma (BG 18.42)), killing him would be a greatly sinful act, and the brāhmaṇa's wife requested that he not be killed.