Why does our Heavenly Father reject self-righteousness through attempts to keep the Law as a means of salvation? What has our Heavenly Father provided as an alternative?

First of all, God the Father warns us that from His vantage point of pure holiness and undefiled righteousness, our works of personal righteousness seeking God’s favor is likened to a “filthy garment,” putrid in smell and appearance (Isaiah 64:6). The Hebrew relevant to Isaiah 64:6 “iddim” (filthy), kat-ta-me (unclean), u-ke-be-ged (rags), actually denotes an unclean woman during menstruation; specifically, a bloody menstrual cloth…this defines the repulsiveness of a man or woman’s works of righteousness when performed in our flesh as opposed to the Holy Spirit’s guidance during the daily process of sanctification relevant to those redeemed by faith in Messiah Jesus (Galatians 5:16; Romans 7:6). Simply put, covenant relationship with our Holy God is NOT possible through human effort, period (Galatians 2:16; Romans 3:20; Ephesians 2:8-9).

Second, no one will be justified by the Law because the purpose of the Law is to arbitrate free will by defining our sin and convicting the conscience thereby promoting societal harmony and thwarting societal implosion/extinction via unrestrained narcissism (Romans 3:20). Law was and is given for the lawless, the undisciplined, the rebellious…law is not given for the righteous (1 Timothy 1:9).

Third, pursuing righteousness through Law-Keeping is not possible due to the sin-nature inherited from Adam (Romans 5:12; Romans 8:1-8) as the Law mandates absolute perfection (James 2:10) and all of humanity is cursed by the Law (Galatians 3:10; Deuteronomy 27:26) as all have sinned and fallen short of our Heavenly Father’s pure and righteous standard i.e. perfection (Romans 3:23; Ecclesiastes 7:20; Romans 3:10).

Fourth, the written code; the Law Covenant; Sinai’s Commandments; the 603 Mosaic Laws; the natural law of conscience (Romans 2:14-15), are simply insufficient in and of themselves to address every aspect of life where personal discernment and wisdom are called into play via a myriad of choices between good v. evil, right v. wrong, pleasing God v. sin. Law, the written code, is simply an insufficient entity to control behavior or define every nuance of daily discernment in our efforts to please God through obedience and Law is subjective, its elements open to interpretation and subject to obfuscation and rationalization by the sin-nature and man’s propensity for narcissism e.g. the pursuit of pleasing the flesh; therefore, our Heavenly Father, before Time began (2 Timothy 1:8-10), instituted the precepts of the Gospel via a future “New Covenant” where man’s relationship with God would be managed, controlled, methodically guided, by God the Holy Spirit who lives within, indwells, the faithful, the redeemed, in Messiah (Ezekiel 36:27; Jeremiah 31:33; Hebrews 10:16).

In accordance with the mandates of the New Covenant, the indwelling Holy Spirit daily walks the redeemed in obedience to the Father’s will through the conscience via sanctification; this, as the Holy Spirit prepares the redeemed for an eternity of service in the New Jerusalem. The unfathomable myriad of laws in the written code are managed by the Spirit who intercedes in the daily life of the redeemed by controlling the conscience via imputed wisdom and discernment apart from enslavement to the impotence and subjectivity of letters and the sin-nature (Romans 7:6).

The Holy Spirit’s internal work in the redeemed is an infinitely superior form of behavioral modification working through the “new creation” in Messiah (2 Corinthians 5:17) as opposed to the Old Law Covenant seeking obedience to a written code by a sin-nature that continuously failed to adhere to the mandates of absolute perfection (James 2:10; Galatians 3:10; Romans 8:1-8).

The only Alternative to the futility of seeking righteousness through Law,

As first pictured by the Holy Spirit in Genesis 3:21, it is Elohim HIMSELF who would provide humanity a “robe of righteousness” through the shedding of innocent blood while rejecting the works of man’s hands to cover his own sin through acts of self-righteousness.

The imputed righteousness of Elohim is defined, pictured, foreshadowed, throughout the Torah and the New Covenant and expressed explicitly in the Gospel of Jesus Christ which was ordained as Elohim’s battle strategy to “destroy the works of the Devil” (1 John 3:8b) “before Time began” (2 Timothy 1:8-10).

The righteousness provided by God the Father is not through the Law but is only attainable by grace (unmerited favor unattainable through human effort) through faith-trust-belief in the One the Father has sent into the World to provide blood atonement for our sin, Jesus Christ (John 3; John 6:29).

The Father has proclaimed ONE-WAY for sinful humanity to enter into an eternal covenant relationship with Him; that is, believe in the Son, Jesus Christ, and receive the indwelling Holy Spirit as Guarantor of covenant relationship and LIVE (John 14:6; Ephesians 1:13-14) via the “imputed” righteousness, the gifted righteousness, of Jesus earned for us through His perfection in keeping the mandates of the Law and giving Himself as a blood sacrifice for our sin (John 3; 2 Corinthians 5:21).

Conclusion,

Elohim has made the sovereign choice to give Himself as a blood sacrifice for your sin; this, for His own glory in the presence of the holy angelic creation, and by faith the perfection, righteousness, of the Son, Jesus Christ, is imputed-gifted into the life of the one who believes that Jesus died for them; this, in exchange for our sin, forever (2 Corinthians 5:21; Hebrews 8:12).

What the Law was powerless to do because it was weakened and nullified as a path to righteousness due to our sinful flesh, Elohim did through the appearing of the perfect, sinless, Son in flesh who has provided mandated blood atonement for the sin of the whole World (John 3: Hebrews 10; 2 Corinthians 5:21; 1 John 2:2).