And Saul was afraid of David, because the Lord was with him,.... Protecting and preserving him, prospering and succeeding him, giving him victory over his enemies, and favour among the people; the Targum is,"the Word of the Lord was for his help.''Procopius Gazaeus interprets it of the Holy Ghost, whose grace was vouchsafed unto him: he might be afraid in his melancholy fits, that as he had attempted to take away the life of David, that David would contrive and seek an opportunity, and take away his life, and seize the kingdom which God had given him, and his being with him strengthened these fears:
and was departed from Saul; so that he was destitute of courage, and greatness of mind, and of wisdom and prudence, and became mean and abject, and exposed himself to the contempt of his subjects.

For a long time David was kept in continual apprehension of falling by the hand of Saul, yet he persevered in meek and respectful behaviour towards his persecutor. How uncommon is such prudence and discretion, especially under insults and provocations! Let us inquire if we imitate this part of the exemplary character before us. Are we behaving wisely in all our ways? Is there no sinful omission, no rashness of spirit, nothing wrong in our conduct? Opposition and perverseness in others, will not excuse wrong tempers in us, but should increase our care, and attention to the duties of our station. Consider Him that endured contradiction of sinners against himself, lest ye be weary and faint in your minds, Hebrews 12:3. If David magnified the honour of being son-in-law to king Saul, how should we magnify the honour of being sons to the King of kings!

Afraid - Lest as he had gained the favour of God and of all the people, he should also take away his kingdom.