John Calvin on John 5:29

29. And they who have done good. He points out believers by good works, as he elsewhere teaches that a tree is known by its fruit, (Matthew 7:16; Luke 6:44.) He praises their good works, to which they have begun to devote themselves since they were called. For the robber, to whom Christ on the cross (Luke 23:42) promised life, and who had all his life been given up to crimes, expresses a desire to do good with his latest breath; but as he is born again a new man, and from being the slave of sin begins to be a servant of righteousness, the whole course of his past life is not taken into account before God. Besides, the sins themselves, on account of which believers every day subject themselves to condemnation, are not imputed to them. For without the pardon which God grants to those who believe in Him, “Sans le pardon que Dieu fait a ses fideles.” there never was a man in the world of whom we can say that he has lived well; nor is there even a single work that will be reckoned altogether good, unless God pardon the sins which belong to it, for all are imperfect and corrupted. Those persons, therefore, are here called doers of good works whom Paul calls earnestly desirous or zealous of them, (Titus 2:14.) But this estimate depends on the fatherly kindness of God, who by free grace approves what deserved to be rejected.

The inference which the Papists draw from those passages — that eternal life is suspended on the merits of works — may be refuted without any difficulty. For Christ does not now treat of the cause of salvation, but merely distinguishes the elect from the reprobate by their own mark; and he does so in order to invite and exhort his own people to a holy and blameless life. And indeed we do not deny that the faith which justifies us is accompanied by an earnest desire to live well and righteously; but we only maintain that our confidence cannot rest on any thing else than on the mercy of God alone.

John 5:30-32

30. I can do nothing of myself; as I hear, I judge, and my judgment is just; because I seek not my own will, but the will of my Father who sent me. 31. If I testify concerning myself, my testimony is not true. 32. There is another who testifieth concerning me, and I know that the testimony which he testifieth concerning me is true.