Titus 3:5

Not by works of righteousness which we have done
The great instance of the kindness and love of God our Saviour is salvation; which the apostle denies that it is brought about by any works, even the best works of men; for "works of righteousness" are works done according to a righteous law, and in obedience to it; and in a righteous manner, from right principles of grace, in faith, and with a view to the glory of God; or otherwise they are not righteous actions, or works of righteousness; wherefore not works before, but after conversion, are here meant; for works before conversion are not properly works of righteousness: besides, these are such which we have done, who formerly were as before described, but now are regenerated and renewed by the Holy Ghost, and created in Christ Jesus unto good works. Now salvation, neither in whole, nor in part, is by these, either as causes; conditions, or means; (See Gill on 2 Timothy 1:9); (hqdu Myvem) , "works of righteousness", is a Jewish phrase used for righteous or good works ^F26

but according to his mercy he saved us;
the mercy of God is natural and essential to him, but the actings and exercise of it, towards this or the other objects, are sovereign and free, and according to his will; the effects of it are many, he is rich and abundant in it; and they are channelled in, and flow forth through the blood and righteousness of Christ; and this is the moving cause of salvation: this moved God to make a covenant with his Son, the blessings of which are the sure mercies of David, and in which God is merciful to the sins and unrighteousnesses of his people; it is owing to the tender mercy of God, that Christ, the dayspring from on high, has visited the earth; and the glory of it is very conspicuous in the affair of redemption by him; the pardon of sin is according to the multitude of God's tender mercies; and regeneration springs from the abundance of it; and even eternal life is the effect of it. Now according to this, God has "saved" his people; salvation is not only a thing determined, and resolved on in the mind of God, but is actually and completely accomplished by Jesus Christ, and an application of it is made to the saints in effectual calling; and because of the certain enjoyment of the whole of it, even eternal glory, the saints are said to be saved already; as they are also in faith and hope, as well as in Christ, their head and representative; (See Gill on Ephesians 2:8). It follows, as the means of salvation,

by the washing of regeneration,
and renewing of the Holy Ghost; by the former is meant, not the ordinance of water baptism; for that is never expressed by washing, nor is it the cause or means of regeneration; the cause being the Spirit of God, and the means the word of God: and besides, persons ought to be regenerated before they are baptized; and they may be baptized, and yet not regenerated, as Simon Magus; nor is it a saving ordinance, or a point of salvation; nor can it be opposed to works of righteousness, as this washing is; for that itself is a work of righteousness; see ( Matthew 3:15 ) and if persons were saved by that, they would be saved by a work of righteousness, contrary to the text itself: but regenerating grace is meant, or a being born of water, and of the Spirit; that is, of the grace of the Spirit, comparable to water for its purity and cleansing virtue: hence such who are regenerated and sanctified, are said to be washed and cleansed, having their hearts purified by faith, and their consciences purged from sin by the blood of Christ: by the latter,

the renewing of the Holy Ghost,
is meant either the fruit and effect of the former, even newness of life and conversation, under the influence of the Holy Spirit; or else the gradual increase and progress of the work of grace upon the soul, renewed day by day in the spirit of the mind, by the Holy Ghost; or rather it means the same thing with regeneration, and is added partly as explanative of the washing of regeneration, showing that that is no other than the new creature, the new man, the new heart, and new spirit, formed in the soul, in the effectual calling; and partly to observe that the Holy Ghost is the author of it. Now it is in this way God saves his people, namely, by regenerating and renewing them; in this is the first appearance and discovery of the love of God to them; this is their open passage into a state of grace, and without this there is no entrance into glory; this is the foundation of all grace and good works, and by which saints appear to be heirs of the heavenly inheritance.