Can some tell me what law Abraham obeyed?
Abraham obeyed my voice. Please notice this is God speaking.
Abraham kept my charge. Strong #H4931 = guard, charge, function, obligation, service, watch
Abraham kept my commandments. Strong #H4687 = mitzvah = 1) commandment
1a) commandment (of man)
1b) the commandment (of God)
1c) commandment (of code of wisdom)
Abraham kept my statutes. Strong #H2708 = chuqquah = statute, ordinance, limit, enactment, something prescribed
Abraham kept my laws. Strong #8451 - Torah = law, direction, instruction
You asked what law Abraham obeyed? Just looking at the word Torah in the Old Testament there are 213 references (KJV)(Strong's #H8451)
Exo_12:49; Exo_13:9; Exo_16:4; Exo_16:28; Exo_18:16; Exo_18:20; Exo_24:12; Lev_6:9; Lev_6:14; Lev_6:25; Lev_7:1; Lev_7:7; Lev_7:11; Lev_7:37; Lev_11:46; Lev_12:7; Lev_13:59; Lev_14:2; Lev_14:32; Lev_14:54; Lev_14:57; Lev_15:32; Lev_26:46; Num_5:29; Num_5:30; Num_6:13; Num_6:21; Num_15:16; Num_15:29; Num_19:2; Num_19:14; Num_31:21; Deu_1:5; Deu_4:8; Deu_4:44; Deu_17:11; Deu_17:18; Deu_17:19; Deu_27:3; Deu_27:8; Deu_27:26; Deu_28:58; Deu_28:61; Deu_29:21; Deu_29:29; Deu_30:10; Deu_31:9; Deu_31:11; Deu_31:12; Deu_31:24; Deu_31:26; Deu_32:46; Deu_33:4; Deu_33:10; Jos_1:7; Jos_1:8; Jos_8:31; Jos_8:32; Jos_8:34; Jos_22:5; Jos_23:6; Jos_24:26; 1Ki_2:3; 2Ki_10:31; 2Ki_14:6; 2Ki_17:13; 2Ki_17:34; 2Ki_17:37; 2Ki_21:8; 2Ki_22:8; 2Ki_22:11; 2Ki_23:24; 2Ki_23:25; 1Ch_16:40; 1Ch_22:12; 2Ch_6:16; 2Ch_12:1; 2Ch_14:4; 2Ch_15:3; 2Ch_17:9; 2Ch_19:10; 2Ch_23:18; 2Ch_25:4; 2Ch_30:16; 2Ch_31:3; 2Ch_31:4; 2Ch_31:21; 2Ch_33:8; 2Ch_34:14; 2Ch_34:15; 2Ch_34:19; 2Ch_35:26; Ezr_3:2; Ezr_7:6; Ezr_7:10; Ezr_10:3; Neh_8:1; Neh_8:2; Neh_8:3; Neh_8:7; Neh_8:8; Neh_8:9; Neh_8:13; Neh_8:14; Neh_8:18; Neh_9:3; Neh_9:13; Neh_9:14; Neh_9:26; Neh_9:29; Neh_9:34; Neh_10:28; Neh_10:29; Neh_10:34; Neh_10:36; Neh_12:44; Neh_13:3; Job_22:22; Psa_1:2; Psa_19:7; Psa_37:31; Psa_40:8; Psa_78:1; Psa_78:5; Psa_78:10; Psa_89:30; Psa_94:12; Psa_105:45; Psa_119:1; Psa_119:18; Psa_119:29; Psa_119:34; Psa_119:44; Psa_119:51; Psa_119:53; Psa_119:55; Psa_119:61; Psa_119:70; Psa_119:72; Psa_119:77; Psa_119:85; Psa_119:92; Psa_119:97; Psa_119:109; Psa_119:113; Psa_119:126; Psa_119:136; Psa_119:142; Psa_119:150; Psa_119:153; Psa_119:163; Psa_119:165; Psa_119:174; Pro_1:8; Pro_3:1; Pro_4:2; Pro_6:20; Pro_6:23; Pro_7:2; Pro_13:14; Pro_28:4; Pro_28:7; Pro_28:9; Pro_29:18; Pro_31:26; Isa_1:10; Isa_2:3; Isa_5:24; Isa_8:16; Isa_8:20; Isa_24:5; Isa_30:9; Isa_42:4; Isa_42:21; Isa_42:24; Isa_51:4; Isa_51:7; Jer_2:8; Jer_6:19; Jer_8:8; Jer_9:13; Jer_16:11; Jer_18:18; Jer_26:4; Jer_31:33; Jer_32:23; Jer_44:10; Jer_44:23; Lam_2:9; Eze_7:26; Eze_22:26; Eze_43:11; Eze_43:12; Eze_44:5; Eze_44:24; Dan_9:10; Dan_9:11; Dan_9:13; Hos_4:6; Hos_8:1; Hos_8:12; Amo_2:4; Mic_4:2; Hab_1:4; Zep_3:4; Hag_2:11; Zec_7:12; Mal_2:6; Mal_2:7; Mal_2:8; Mal_2:9; Mal_4:4;
For the New Testament, the word "Law" is Strong's # G3551 nomos - From a primary word νέμω nemō (to parcel out, especially food or grazing to animals); law (through the idea of prescriptive usage), generally (regulation), specifically (of Moses [including the volume]; also of the Gospel), or figuratively (a principle): - law.
There is 197 uses (KJV) of HG3551:
Mat_5:17; Mat_5:18; Mat_7:12; Mat_11:13; Mat_12:5; Mat_22:36; Mat_22:40; Mat_23:23; Luk_2:22; Luk_2:23; Luk_2:24; Luk_2:27; Luk_2:39; Luk_10:26; Luk_16:16; Luk_16:17; Luk_24:44; Joh_1:17; Joh_1:45; Joh_7:19; Joh_7:23; Joh_7:49; Joh_7:51; Joh_8:5; Joh_8:17; Joh_10:34; Joh_12:34; Joh_15:25; Joh_18:31; Joh_19:7; Act_6:13; Act_7:53; Act_13:15; Act_13:39; Act_15:5; Act_15:24; Act_18:13; Act_18:15; Act_21:20; Act_21:24; Act_21:28; Act_22:3; Act_22:12; Act_23:3; Act_23:29; Act_24:6; Act_24:14; Act_25:8; Act_28:23; Rom_2:12; Rom_2:13; Rom_2:14; Rom_2:15; Rom_2:17; Rom_2:18; Rom_2:20; Rom_2:23; Rom_2:25; Rom_2:26; Rom_2:27; Rom_3:19; Rom_3:20; Rom_3:21; Rom_3:27; Rom_3:28; Rom_3:31; Rom_4:13; Rom_4:14; Rom_4:15; Rom_4:16; Rom_5:13; Rom_5:20; Rom_6:14; Rom_6:15; Rom_7:1; Rom_7:2; Rom_7:3; Rom_7:4; Rom_7:5; Rom_7:6; Rom_7:7; Rom_7:8; Rom_7:9; Rom_7:12; Rom_7:14; Rom_7:16; Rom_7:21; Rom_7:22; Rom_7:23; Rom_7:25; Rom_8:2; Rom_8:3; Rom_8:4; Rom_8:7; Rom_9:31; Rom_9:32; Rom_10:4; Rom_10:5; Rom_13:8; Rom_13:10; 1Co_7:39; 1Co_9:8; 1Co_9:9; 1Co_9:20; 1Co_14:21; 1Co_14:34; 1Co_15:56; Gal_2:16; Gal_2:19; Gal_2:21; Gal_3:2; Gal_3:5; Gal_3:10; Gal_3:11; Gal_3:12; Gal_3:13; Gal_3:17; Gal_3:18; Gal_3:19; Gal_3:21; Gal_3:23; Gal_3:24; Gal_4:4; Gal_4:5; Gal_4:21; Gal_5:3; Gal_5:4; Gal_5:14; Gal_5:18; Gal_5:23; Gal_6:2; Gal_6:13; Eph_2:15; Php_3:5; Php_3:6; Php_3:9; 1Ti_1:8; 1Ti_1:9; Heb_7:5; Heb_7:12; Heb_7:16; Heb_7:19; Heb_7:28; Heb_8:4; Heb_8:10; Heb_9:19; Heb_9:22; Heb_10:1; Heb_10:8; Heb_10:16; Heb_10:28; Jas_1:25; Jas_2:8; Jas_2:9; Jas_2:10; Jas_2:11; Jas_2:12; Jas_4:11;
Here is just from the book of James regarding Torah utilizing Complete Jewish Bible:
(Jas 1:25) But if a person looks closely into the perfect Torah, which gives freedom, and continues, becoming not a forgetful hearer but a doer of the work it requires, then he will be blessed in what he does.
(Jas 2:8) If you truly attain the goal of Kingdom Torah, in conformity with the passage that says, "Love your neighbor as yourself," you are doing well.
(Jas 2:9) But if you show favoritism, your actions constitute sin, since you are convicted under the Torah as transgressors.
(Jas 2:10) For a person who keeps the whole Torah, yet stumbles at one point, has become guilty of breaking them all.
(Jas 2:11) For the One who said, "Don't commit adultery," also said, "Don't murder." Now, if you don't commit adultery but do murder, you have become a transgressor of the Torah.
(Jas 2:12) Keep speaking and acting like people who will be judged by a Torah which gives freedom.
(Jas 4:11) Brothers, stop speaking against each other! Whoever speaks against a brother or judges a brother is speaking against Torah and judging Torah. And if you judge Torah, you are not a doer of what Torah says, but a judge.
(Jas 4:12) There is but one Giver of Torah; he is also the Judge, with the power to deliver and to destroy. Who do you think you are, judging your fellow human being?
Also using the Greek Septuagint with Strong's #G3551, there are 232 references in the Old Testament. They are:
Exo_12:43; Exo_12:49; Exo_13:9; Exo_13:10; Exo_16:4; Exo_16:28; Exo_18:16; Exo_18:20; Exo_24:12; Lev_6:9; Lev_6:14; Lev_6:22; Lev_6:25; Lev_7:1; Lev_7:7; Lev_7:11; Lev_7:37; Lev_11:46; Lev_12:7; Lev_13:59; Lev_14:2; Lev_14:32; Lev_14:54; Lev_14:57; Lev_15:3; Lev_15:32; Lev_19:19; Lev_19:37; Lev_26:46; Num_5:29; Num_5:30; Num_6:13; Num_6:21; Num_9:3; Num_9:12; Num_9:14; Num_15:15; Num_15:16; Num_15:29; Num_19:2; Num_19:14; Num_31:21; Deu_1:5; Deu_4:8; Deu_4:44; Deu_17:11; Deu_24:8; Deu_27:3; Deu_27:8; Deu_27:26; Deu_28:58; Deu_28:61; Deu_29:20; Deu_29:21; Deu_29:27; Deu_29:29; Deu_30:10; Deu_31:9; Deu_31:11; Deu_31:12; Deu_31:24; Deu_31:26; Deu_32:44; Deu_32:46; Deu_33:4; Deu_33:10; Jos_1:8; Jos_8:31; Jos_8:32; Jos_8:34; Jos_22:5; Jos_23:6; Jos_24:25; Jos_24:26; 2Sa_7:19; 1Ki_2:3; 2Ki_10:31; 2Ki_14:6; 2Ki_17:13; 2Ki_17:34; 2Ki_17:37; 2Ki_22:8; 2Ki_22:11; 2Ki_23:24; 2Ki_23:25; 1Ch_16:40; 1Ch_22:12; 2Ch_6:16; 2Ch_14:4; 2Ch_15:3; 2Ch_17:9; 2Ch_23:18; 2Ch_25:4; 2Ch_31:3; 2Ch_31:21; 2Ch_33:8; 2Ch_34:14; 2Ch_34:15; 2Ch_34:19; 2Ch_35:19; 2Ch_35:26; Ezr_3:2; Ezr_7:6; Ezr_7:10; Ezr_7:12; Ezr_7:14; Ezr_7:21; Ezr_7:25; Ezr_7:26; Ezr_10:3; Neh_8:1; Neh_8:2; Neh_8:3; Neh_8:7; Neh_8:8; Neh_8:9; Neh_8:13; Neh_8:14; Neh_8:18; Neh_9:3; Neh_9:13; Neh_9:14; Neh_9:26; Neh_9:29; Neh_9:34; Neh_10:28; Neh_10:29; Neh_10:34; Neh_10:36; Neh_13:3; Est_1:8; Est_1:13; Est_1:15; Est_1:19; Est_1:20; Est_3:8; Est_4:16; Est_8:11; Job_34:27; Psa_1:2; Psa_19:7; Psa_37:31; Psa_40:8; Psa_78:1; Psa_78:5; Psa_78:10; Psa_89:30; Psa_94:12; Psa_105:45; Psa_119:1; Psa_119:18; Psa_119:29; Psa_119:34; Psa_119:44; Psa_119:51; Psa_119:53; Psa_119:55; Psa_119:57; Psa_119:61; Psa_119:70; Psa_119:72; Psa_119:77; Psa_119:85; Psa_119:92; Psa_119:97; Psa_119:109; Psa_119:113; Psa_119:126; Psa_119:136; Psa_119:142; Psa_119:150; Psa_119:153; Psa_119:163; Psa_119:165; Psa_119:174; Psa_130:5; Pro_3:16; Pro_4:2; Pro_6:20; Pro_6:23; Pro_9:10; Pro_13:14; Pro_13:15; Pro_28:4; Pro_28:7; Pro_28:9; Pro_29:18; Isa_1:10; Isa_2:3; Isa_5:24; Isa_8:16; Isa_8:20; Isa_19:2; Isa_24:5; Isa_24:16; Isa_30:9; Isa_33:6; Isa_42:24; Isa_51:4; Isa_51:7; Jer_2:8; Jer_6:19; Jer_8:8; Jer_9:13; Jer_16:11; Jer_18:18; Jer_23:27; Jer_31:33; Jer_31:37; Jer_44:23; Jer_49:12; Lam_2:9; Eze_7:26; Eze_22:26; Dan_7:25; Dan_9:10; Dan_9:11; Dan_9:13; Hos_4:6; Hos_8:1; Amo_2:4; Amo_4:5; Mic_4:2; Hab_1:4; Zep_3:4; Hag_2:11; Zec_7:12; Mal_2:6; Mal_2:7; Mal_2:8; Mal_2:9; Mal_4:4;
I hope this helps to see the full continuity of the Word, both Old and New Covenenant that God's laws/commandments written in the Pentateuch (Torah - 1st five books of OT) are the same laws and commandments Jesus and the disciples are also upholding (ie not done away with). Many have misunderstood Paul and will quote him as though he is saying the law is not to be obeyed. I have many lessons on the Pauline Paradox if interested.