King James Version (KJV)
And let it be, when these signs are come unto thee, {that} thou do as occasion serve thee; for God {is} with thee. {And...: Heb. And it shall come to pass, that when these signs, etc} {that...: Heb. do for thee as thine hand shall find}
Modern English
Let it be, when these signs have come to you, that you do what is appropriate for the occasion; for God is with you.
Hebrew
וְהָיָ֗ה כִּ֥י תבאינה תָבֹ֛אנָה הָאֹת֥וֹת הָאֵ֖לֶּה לָ֑ךְ עֲשֵׂ֤ה לְךָ֙ אֲשֶׁ֣ר תִּמְצָ֣א יָדֶ֔ךָ כִּ֥י הָאֱלֹהִ֖ים עִמָּֽךְ׃
vhayah kiy tbʾynh taboʾnah haʾotvot haʾeleh lak ʿasheh lka ʾasher timṣaʾ yadeka kiy haʾelohiym ʿimak