Nay, we establish the law (alla nomon histanomen). Present indicative active of late verb histanō from histēmi. This Paul hinted at in Rom 3:21. How he will show in chapter 4 how Abraham himself is an example of faith and in his life illustrates the very point just made. Besides, apart from Christ and the help of the Holy Spirit no one can keep God’s law. The Mosaic law is only workable by faith in Christ.