This really depends on the stage your company is at. If you haven't found product-market fit, you need to spend a majority of your time in sales mode talking to potential customers/users so you can figure out who your ideal market is and what your market wants. If you try to start marketing without finding product-market fit, you may end up wasting a lot of time and money without knowing whether anyone even wants your product.

It also depends on who you're selling to as well. Consumer/SMB customers may require less sales efforts than enterprise customers. You will always want to start with talking to users regardless, which is sales.