Jamieson, Fausset and Brown on Psalms 105:42-45

42-45. The reasons for these dealings: (1) God's faithfulness to His covenant, "His holy promise" of Canaan, is the fountain whence flowed so many acts of marvellous kindness to His people (compare Psa 105:8, 11). Ex 2:24 is the fundamental passage [Hengstenberg]. (2) That they might be obedient. The observance of God's commands by Abraham was the object of the covenant with him (Ge 18:19), as it was also the object of the covenant with Israel, that they might observe God's statutes.

remembered ... and Abraham--or, "remembered His holy word (that is, covenant confirmed) with Abraham."