But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.
Looketh into, х parakupsas (G3879)] - stoopeth down to take a close look. Peers into: stronger than "beholdeth" (James 1:24). A blessed curiosity if efficacious in bearing fruit (Bengel).
Perfect law of liberty - the Gospel-rule of life, perfect and perfecting (shown in the sermon on the mount, Matthew 5:48): making us truly walk at liberty (Psalms 119:32; Psalms 119:45). Christians should aim at a higher standard than was generally understood under the law. The principle of love takes the place of the letter of the law, so that by the Spirit they are free from the yoke of sin, obeying by spontaneous instinct (James 2:8; James 2:10; James 2:12; John 8:31-36; John 15:14-15: cf. 1 Corinthians 7:22; Galatians 5:1; Galatians 5:13; 1 Peter 2:16). The law is thus not made void, but fulfilled.
Continueth therein - contrast "goeth his way," James 1:24: continueth both looking into God's Word and doing its percepts.
Doer of the work - rather, 'of work:' an actual worker.
Blessed in his deed, х poieesei (G4162)] - 'in his doing:' the very doing is blessedness (Psalms 19:11).