Albert Barnes on John 12:50

Is life everlasting. Is the cause or source of everlasting life. He that obeys the commandment of God shall obtain everlasting life; and this is his commandment, that we believe in the name of his only-begotten Son, 1Jn 3:22. We see here the reason of the earnestness and fidelity of the Lord Jesus. It was because he saw that eternal life depended on the faithful preaching of the message of God. He therefore proclaimed it in the face of all opposition, contempt, and persecution. And we see also,

1st. That every minister of religion should have a deep and abiding conviction that he delivers a message that is to be connected with the eternal welfare of his hearers. And,

2nd. Under the influence of this belief, he should fearlessly deliver his message in the face of bonds, poverty, contempt, persecution, and death.

It may not be improper to remark here that this is the close of the public preaching of Christ. The rest of his ministry was employed in the private instruction of his apostles, and in preparing them for his approaching death. It is such a close as all his ministers should desire to make--a solemn, deliberate, firm exhibition of the truth of God, under a belief that on it was depending the eternal salvation of his hearers, and uttering without fear the solemn message of the Most High to a lost world.

(z) "his commandments" 1Jn 3:22