Joshua said, ‘Now therefore revere the Lord, and serve him in sincerity and in faithfulness; put away the gods that your ancestors served beyond the River and in Egypt, and serve the Lord. Now if you are unwilling to serve the Lord, choose this day whom you will serve, whether the gods your ancestors served in the region beyond the River or the gods of the Amorites in whose land you are living; but as for me and my household, we will serve the Lord.’
Then the people answered, ‘Far be it from us that we should forsake the Lord to serve other gods; for it is the Lord our God who brought us and our ancestors up from the land of Egypt, out of the house of slavery, and who did those great signs in our sight. He protected us along all the way that we went, and among all the peoples through whom we passed; and the Lord drove out before us all the peoples, the Amorites who lived in the land. Therefore we also will serve the Lord, for he is our God.’
(Lectionary, New Revised Standard Version)
There are basically two kinds of promises really it seems to me, one is positive and one negative. "I will give up cigarettes, or chocolate!" is the negative - that is, something we give up or stop doing. The positive promise is one where we take on a challenge or do something new and creative, like cycling so many miles to raise money for a charity, or promise to have our head shaved to support a friend going through chemotherapy treatment for cancer.
Some promises only we (and God) know if we've kept them, especially the "I promise not to be critical of Mrs ??" kind! Others are much more public like those made by witnesses in trials that start "I promise to tell the truth, the whole truth and nothing but the truth. So help me, God." I am reminded at this moment of the many times I swore publicly on the bible to uphold the Christian faith when becoming the new vicar of a parish or parishes. Also remembered is the time in 1965 I promised to love, honour, and cherish my husband.
In today's reading Joshua is coming to the end of his life. He appoints no single leader, in charge of the twelve tribes, preferring to leave it to individual tribal leaders to lead the people. However, he does need to make sure that the whole nation remains firmly aligned to Yahweh (God) since they are surrounded by people who worship different gods. After his own public affirmation of God, we see the people firmly promise their allegiance , saying "We also will serve the Lord, for he is our God."
Father-God,
we have often firmly promised to obey You -
at our Baptism or renewal of baptismal vows,
or at our Confirmation,
and sometimes in the secret of our heart.
Only You know how quickly we break these promises,
and then desperately remake them.
Forgive us, and strengthen us with Your Spirit
so that we make and keep our promises to You.
Amen.
Wikihow has some interesting thoughts on how to keep a promise to other people:
Or look at this, about God's promises to us: