1 Samuel 12:24

Only fear the Lord, and serve him in truth with all your
heart
Fear him not with a servile fear, which is before dehorted from, but with a filial fear, a reverential affection for God; and includes the whole of religious worship, internal and external; explained further by serving him according to the truth of his word, and in a cordial, sincere, and affectionate manner; and if this was wanting in them, he suggests that his prayers and instructions would be of little avail, and not to be depended on:

for consider how great things he hath done for you;
in bringing them out of Egypt: settling them in the land of Canaan; giving them his laws, statutes, commands, and ordinances; sending prophets unto them, and raising up judges for them, and bestowing all good things on them, in nature, providence, and grace; though some restrain this to the great thing he had done that day, to convince them of their sin, and by which they were returned to the Lord, namely, the violent storm of thunder; which wonderful instance of the power of God, and token of his displeasure against them, they were to lay up in their minds, and not forget, that it might be a means of preserving them from sin for the future.