In this verse, Hashem promises that if we listen to His commandments, He will bless us and multiply us, and grant us success in the Land of Israel. The Hebrew word for ‘and if you do,’ eikev (עקב), also means ‘heel.’ Rashi quotes the Sages who teach that the use of the word eikev hints to the fact that we must keep all the commandments equally, even the ones that seem unimportant, which people tend to figuratively step on with their heels. If we are careful to follow all the commandments of Hashem, even the seemingly insignificant ones, then we will certainly be rewarded with great blessings in the Promised Land.