Translation:

14. Then when We decreed (Solomon's) death nothing showed them his death except a little worm of the earth which kept (slowly) gnawing away at his staff: so when he fell down the Jinns saw plainly that if they had known the unseen they would not have tarried in the humiliating Penalty (of their Task).

Notes (Tafseer)

3808. This statement illustrates three points: (1) however great and glorious human power and grandeur may be, it is only for a time, and it may fade away even before people know of its decline; (2) the most remarkable events may be brought to light, not by a flourish of trumpets, but by a humble individual, unknown and unseen, who works imperceptibly and undermines even so strong a thing as staff, on which a great man may lean; (3) work done by men merely on the basis of brute Strength or fear, as in the case of the Jinns, will not endure. This is brought up in strong contrast against the Power and Majesty of Allah, which will endure, which cannot be sapped, and which can only be fully appreciated by a training of the will and heart. In the same way, in David's story above, his mighty strength as a warrior (see ii. 251) and his skill in making armour are only to be valued when used, as it was used, in the service of Allah, in righteous works (xxxiv. 1 1).

3809. The Jinns looked upon their work as a Penalty, and so it became to them. The people who worked at the Temple of Solomon as the People of David worked and gloried in their work as a thanksgiving to Allah, and their work became sanctified. The Jinns knew nothing of hidden secrets; they only saw the obvious, and had not even the significance of the little worm that slowly gnawed away Solomon's staff.