The Spanish tener (to hold) comes from the Latin tenere for the same.
From the same root tenere, we get the English tenet — think about it, you hold your beliefs.
And it gets even better: from tenere, we also get the English suffix ‑tain, as in maintain, sustain, contain, detain, obtain, and entertain. And the -tain words map almost identically to the Spanish suffix of the same, the same -tener!
For example, mano, the Spanish for hand, is the same mano in maintain (or mantener, in Spanish) — which thus literally means, “to hold in your hand”!