Will he make a covenant with thee? - That is, will he submit himself to thee, and enter into a compact to serve thee? Such a compact was made by those who agreed to serve another; and the idea here is, that the animal here referred to could not be reduced to such service - that is, could not be tamed.
Wilt thou take him for a servant for ever? - Canst thou so subdue him that he will be a perpetual slave? The meaning of all this is, that he was an untamable animal, and could not be reduced, as many others could, to domestic use.

Will he make a covenant - Canst thou hire him as thou wouldst a servant, who is to be so attached to thy family as to have his ear bored, that he may abide in thy house for ever? Is not this an allusion to the law, Exodus 21:1-6?

Will he make a covenant with thee? wilt thou take (n) him for a servant for ever?
(n) To do your business, and be at your command?

Will he make a covenant with thee?.... To live in friendship or servitude, as follows;
wilt thou take him for a servant for ever? oblige him to serve thee for life, or reduce him to perpetual bondage; signifying, that he is not to be tamed or brought into subjection; which is true of the whale, but not of the crocodile; for several authors (i) speak of them as making a sort of a truce with the priests of Egypt for a certain time, and of their being tamed so as to be handled, and fed, and brought up in the house.
(i) Herodot, ut supra, (Euterpe, sive, l. 2.) c. 69. Aelian. l. 8. c. 2. & l. 10. c. 21. Solin. c. 45. Plin. l. 8. c. 46.

Can he be tamed for domestic use (so Job 39:10-12)?